diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 1b182740c..248e111f9 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -21,11 +21,11 @@ Your PR description goes here.
 
 - [ ] New country holidays support (thank you!)
 - [ ] Supported country holidays update (calendar discrepancy fix, localization)
-- [ ] Existing code/tests/processes improvement (best practice, refactoring, optimization)
+- [ ] Existing code/test/process improvement (best practice, cleanup, refactoring, optimization)
 - [ ] Dependency upgrade (version update)
 - [ ] Bugfix (non-breaking change which fixes an issue)
 - [ ] Breaking change (a code change causing existing functionality to break)
-- [ ] New feature (adds functionality to python-holidays in general)
+- [ ] New feature (new python-holidays functionality in general)
 
 ## Checklist
 
@@ -33,12 +33,12 @@ Your PR description goes here.
   Put an `x` in the boxes that apply. You can change them after PR is created.
 -->
 
-- [ ] I've followed the [contributing guidelines][contributing-guidelines]
-- [ ] This PR is filed against `beta` branch of the repository
-- [ ] This PR doesn't contain any merge conflicts
-- [ ] The code style looks good (`make pre-commit`)
-- [ ] I've added tests to verify that the new code works and all tests pass locally (`make test`)
-- [ ] The related [documentation][docs] has been added/updated (check off the box for free if no updates is required)
+- [x ] I've followed the [contributing guidelines][contributing-guidelines]
+- [x ] This PR is filed against `beta` branch of the repository
+- [x ] This PR doesn't contain any merge conflicts and has clean commit history
+- [x ] The code style looks good (`make pre-commit`)
+- [x ] I've added tests to verify that the new code works and all tests pass locally (`make test`, `make tox`)
+- [x ] The related [documentation][docs] has been added/updated (check off the box for free if no updates is required)
 
 <!--
   Thanks again for your contribution!
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 35aa34989..f4da3cee5 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -58,6 +58,11 @@ repos:
       - id: rstcheck
         additional_dependencies: [rstcheck, sphinx]
 
+  - repo: https://github.com/tox-dev/tox-ini-fmt
+    rev: "0.6.1"
+    hooks:
+      - id: tox-ini-fmt
+
   - repo: https://github.com/asottile/setup-cfg-fmt
     rev: v2.2.0
     hooks:
diff --git a/CHANGES b/CHANGES
index e6fc6c852..943abe776 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,36 @@
+Version 0.21
+============
+
+Released March 6, 2023
+
+- Refactor `HolidayBase::get_named`, #991 (@arkid15r)
+- Refactor calendars: extract to a separate module, #969 (@arkid15r)
+- Refactor common.TestCase, #979 (@arkid15r)
+- Refactor relative weekdays calculation: replace relativedelta, #1002 (@KJhellico)
+- Fix NYSE New Year's Day observance calculation, #1000 (@KJhellico)
+- Fix tox.ini typo, #994 (@mborsetti)
+- Improve Argentina holidays, #988 (@PPsyrius)
+- Optimize Azerbaijan observed holidays, #961 (@KJhellico)
+- Optimize Malaysia observed holidays, #963 (@KJhellico)
+- Optimize Nigeria observed holidays, #978 (@KJhellico)
+- Update Argentina holidays. Add holidays localization: uk, #968 (@KJhellico)
+- Update Chile holidays. Add localization: en_US, es, uk, #990 (@KJhellico)
+- Update Ireland holidays: St. Bridget's Day, #953 (@PPsyrius)
+- Update Japan holidays localization: en_US, #964 (@KJhellico)
+- Update Mexico holidays, #980 (@KJhellico)
+- Update PR template, #997 (@arkid15r)
+- Update Saudi Arabia holidays, #962 (@KJhellico)
+- Add Canada holidays localization: th, #986 (@PPsyrius)
+- Add Colombia holidays localization: en_US, es, uk, #965 (@KJhellico)
+- Add Monaco holidays localization: en_US, fr, uk, #966 (@KJhellico)
+- Add Thailand holidays localization: en_US, th, #946 (@PPsyrius)
+- Add functions for relative weekdays calculation, #989 (@KJhellico)
+- Add tox-ini-fmt to .pre-commit-config.yaml, #999 (@arkid15r)
+- Clean up Malaysia tests, #996 (@KJhellico)
+- Clean up Thailand localization and in-line code comments, #995 (@PPsyrius)
+- Clean up tests module loading, #992 (@arkid15r)
+- Use the built-in library for time zone functions, #993 (@mborsetti)
+
 Version 0.20
 ============
 
diff --git a/README.rst b/README.rst
index f772edfc2..6050d99e4 100644
--- a/README.rst
+++ b/README.rst
@@ -528,7 +528,7 @@ default language code is a `ISO 639-1 code`_.
      - Supported languages
    * - Argentina
      - es
-     - en_US, es
+     - en_US, es, uk
    * - Armenia
      - hy
      - en_US, hy
@@ -541,6 +541,12 @@ default language code is a `ISO 639-1 code`_.
    * - Canada
      - en
      - en, fr
+   * - Chile
+     - es
+     - en_US, es, uk
+   * - Colombia
+     - es
+     - en_US, es, uk
    * - Cyprus
      - el
      - el, en
@@ -559,6 +565,12 @@ default language code is a `ISO 639-1 code`_.
    * - Japan
      - ja
      - en_US, ja
+   * - Monaco
+     - fr
+     - en_US, fr, uk
+   * - Peru
+     - es
+     - en_US, es, uk
    * - Poland
      - pl
      - en_US, pl, uk
@@ -568,6 +580,9 @@ default language code is a `ISO 639-1 code`_.
    * - Serbia
      - sr
      - en_US, sr
+   * - Thailand
+     - th
+     - en_US, th
    * - Ukraine
      - uk
      - en_US, uk
diff --git a/holidays/__init__.py b/holidays/__init__.py
index cdc881fd9..ac796d7a7 100644
--- a/holidays/__init__.py
+++ b/holidays/__init__.py
@@ -15,4 +15,4 @@
 from holidays.holiday_base import *
 from holidays.utils import *
 
-__version__ = "0.20"
+__version__ = "0.21"
diff --git a/holidays/calendars.py b/holidays/calendars.py
new file mode 100644
index 000000000..90c17766a
--- /dev/null
+++ b/holidays/calendars.py
@@ -0,0 +1,936 @@
+#  python-holidays
+#  ---------------
+#  A fast, efficient Python library for generating country, province and state
+#  specific sets of holidays on the fly. It aims to make determining whether a
+#  specific date is a holiday as fast and flexible as possible.
+#
+#  Authors: dr-prodigy <dr.prodigy.github@gmail.com> (c) 2017-2023
+#           ryanss <ryanssdev@icloud.com> (c) 2014-2017
+#  Website: https://github.com/dr-prodigy/python-holidays
+#  License: MIT (see LICENSE file)
+
+from datetime import date
+from datetime import timedelta as td
+from functools import lru_cache
+from typing import Iterable, Optional
+
+from hijri_converter import convert
+from hijri_converter.ummalqura import GREGORIAN_RANGE, HIJRI_RANGE
+
+
+def _islamic_to_gre(g_year: int, h_month: int, h_day: int) -> Iterable[date]:
+    """
+    Find the Gregorian dates of all instances of Islamic (Lunar Hijrī) calendar
+    month and day falling within the Gregorian year. There could be up to two
+    such instances in a single Gregorian year since the Islamic (Lunar Hijrī)
+    calendar is about 11 days shorter.
+
+    Relies on package `hijri_converter
+    <https://www.pypi.org/project/hijri_converter>__.
+
+    :param g_year:
+        The Gregorian year.
+
+    :param h_month:
+        The Lunar Hijrī (Islamic) month.
+
+    :param h_day:
+        The Lunar Hijrī (Islamic) day.
+
+    :return:
+        An Iterable of Gregorian dates within the Gregorian year specified
+        that matches the Islamic (Lunar Hijrī) calendar day and month
+        specified. An empty Iterable is returned if the Gregorian year
+        is outside of the covered period, which as of hijri_converter 2.2.4
+        (in January 2023) is Gregorian years 1925 to 2076 inclusive, or
+        equal to the contents of hijri_converter.ummalqura.GREGORIAN_RANGE
+        plus/minus 1 year.
+    """
+
+    # To avoid hijri_converter check range OverflowError.
+    g_year_min, g_year_max = (d[0] for d in GREGORIAN_RANGE)
+    h_year_min, h_year_max = (d[0] for d in HIJRI_RANGE)
+    if g_year <= g_year_min or g_year > g_year_max:
+        return ()
+
+    h_year = convert.Gregorian(g_year, 1, 1).to_hijri().year
+    h_years = (
+        y for y in range(h_year, h_year + 3) if h_year_min <= y <= h_year_max
+    )
+    gre_dates = (
+        convert.Hijri(y, h_month, h_day).to_gregorian() for y in h_years
+    )
+    return (gre_date for gre_date in gre_dates if gre_date.year == g_year)
+
+
+def _get_nth_weekday_from(n: int, weekday: int, from_dt: date) -> date:
+    """
+    Return date of a n-th weekday after (n is positive)
+    or before (n is negative) a specific date
+    (e.g. 1st Monday, 2nd Saturday, etc).
+    """
+
+    if n > 0:
+        delta = (n - 1) * 7 + (weekday - from_dt.weekday()) % 7
+    else:
+        delta = (n + 1) * 7 - (from_dt.weekday() - weekday) % 7
+    return from_dt + td(days=delta)
+
+
+def _get_nth_weekday_of_month(
+    n: int, weekday: int, month: int, year: int
+) -> date:
+    """
+    Return date of n-th weekday of month for a specific year
+    (e.g. 1st Monday of Apr, 2nd Friday of June, etc).
+    If n is negative the countdown starts at the end of month
+    (i.e. -1 is last).
+    """
+
+    if n < 0:
+        month += 1
+        if month > 12:
+            month = 1
+            year += 1
+        start_date = date(year, month, 1) + td(days=-1)
+    else:
+        start_date = date(year, month, 1)
+    return _get_nth_weekday_from(n, weekday, start_date)
+
+
+class _ChineseLuniSolar:
+    def __init__(self) -> None:
+        """
+        This class has functions that generate Gregorian dates for holidays
+        based on the Chinese lunisolar calendar.
+
+        See `Wikipedia
+        <https://en.wikipedia.org/wiki/Chinese_New_Year#Dates_in_Chinese_\
+        lunisolar_calendar>`__
+
+        Usage example:
+
+        >>> from holidays.calendars import _ChineseLuniSolar
+        >>> cnls = _ChineseLuniSolar()
+        >>> print(cnls.lunar_n_y_date(2010))
+        2010-02-14
+        """
+
+        # A binary representation starting from year 1901 of the number of
+        # days per year, and the number of days from the 1st to the 13th to
+        # store the monthly (including the month of the month). 1 means that
+        # the month is 30 days. 0 means the month is 29 days.
+        # The 12th to 15th digits indicate the month of the next month.
+        # If it is 0x0F, it means that there is no leap month.
+        self.G_LUNAR_MONTH_DAYS = [
+            0xF0EA4,  # 1901
+            0xF1D4A,
+            0x52C94,
+            0xF0C96,
+            0xF1536,
+            0x42AAC,
+            0xF0AD4,
+            0xF16B2,
+            0x22EA4,
+            0xF0EA4,  # 1911
+            0x6364A,
+            0xF164A,
+            0xF1496,
+            0x52956,
+            0xF055A,
+            0xF0AD6,
+            0x216D2,
+            0xF1B52,
+            0x73B24,
+            0xF1D24,  # 1921
+            0xF1A4A,
+            0x5349A,
+            0xF14AC,
+            0xF056C,
+            0x42B6A,
+            0xF0DA8,
+            0xF1D52,
+            0x23D24,
+            0xF1D24,
+            0x61A4C,  # 1931
+            0xF0A56,
+            0xF14AE,
+            0x5256C,
+            0xF16B4,
+            0xF0DA8,
+            0x31D92,
+            0xF0E92,
+            0x72D26,
+            0xF1526,
+            0xF0A56,  # 1941
+            0x614B6,
+            0xF155A,
+            0xF0AD4,
+            0x436AA,
+            0xF1748,
+            0xF1692,
+            0x23526,
+            0xF152A,
+            0x72A5A,
+            0xF0A6C,  # 1951
+            0xF155A,
+            0x52B54,
+            0xF0B64,
+            0xF1B4A,
+            0x33A94,
+            0xF1A94,
+            0x8152A,
+            0xF152E,
+            0xF0AAC,
+            0x6156A,  # 1961
+            0xF15AA,
+            0xF0DA4,
+            0x41D4A,
+            0xF1D4A,
+            0xF0C94,
+            0x3192E,
+            0xF1536,
+            0x72AB4,
+            0xF0AD4,
+            0xF16D2,  # 1971
+            0x52EA4,
+            0xF16A4,
+            0xF164A,
+            0x42C96,
+            0xF1496,
+            0x82956,
+            0xF055A,
+            0xF0ADA,
+            0x616D2,
+            0xF1B52,  # 1981
+            0xF1B24,
+            0x43A4A,
+            0xF1A4A,
+            0xA349A,
+            0xF14AC,
+            0xF056C,
+            0x60B6A,
+            0xF0DAA,
+            0xF1D92,
+            0x53D24,  # 1991
+            0xF1D24,
+            0xF1A4C,
+            0x314AC,
+            0xF14AE,
+            0x829AC,
+            0xF06B4,
+            0xF0DAA,
+            0x52D92,
+            0xF0E92,
+            0xF0D26,  # 2001
+            0x42A56,
+            0xF0A56,
+            0xF14B6,
+            0x22AB4,
+            0xF0AD4,
+            0x736AA,
+            0xF1748,
+            0xF1692,
+            0x53526,
+            0xF152A,  # 2011
+            0xF0A5A,
+            0x4155A,
+            0xF156A,
+            0x92B54,
+            0xF0BA4,
+            0xF1B4A,
+            0x63A94,
+            0xF1A94,
+            0xF192A,
+            0x42A5C,  # 2021
+            0xF0AAC,
+            0xF156A,
+            0x22B64,
+            0xF0DA4,
+            0x61D52,
+            0xF0E4A,
+            0xF0C96,
+            0x5192E,
+            0xF1956,
+            0xF0AB4,  # 2031
+            0x315AC,
+            0xF16D2,
+            0xB2EA4,
+            0xF16A4,
+            0xF164A,
+            0x63496,
+            0xF1496,
+            0xF0956,
+            0x50AB6,
+            0xF0B5A,  # 2041
+            0xF16D4,
+            0x236A4,
+            0xF1B24,
+            0x73A4A,
+            0xF1A4A,
+            0xF14AA,
+            0x5295A,
+            0xF096C,
+            0xF0B6A,
+            0x31B54,  # 2051
+            0xF1D92,
+            0x83D24,
+            0xF1D24,
+            0xF1A4C,
+            0x614AC,
+            0xF14AE,
+            0xF09AC,
+            0x40DAA,
+            0xF0EAA,
+            0xF0E92,  # 2061
+            0x31D26,
+            0xF0D26,
+            0x72A56,
+            0xF0A56,
+            0xF14B6,
+            0x52AB4,
+            0xF0AD4,
+            0xF16CA,
+            0x42E94,
+            0xF1694,  # 2071
+            0x8352A,
+            0xF152A,
+            0xF0A5A,
+            0x6155A,
+            0xF156A,
+            0xF0B54,
+            0x4174A,
+            0xF1B4A,
+            0xF1A94,
+            0x3392A,  # 2081
+            0xF192C,
+            0x7329C,
+            0xF0AAC,
+            0xF156A,
+            0x52B64,
+            0xF0DA4,
+            0xF1D4A,
+            0x41C94,
+            0xF0C96,
+            0x8192E,  # 2091
+            0xF0956,
+            0xF0AB6,
+            0x615AC,
+            0xF16D4,
+            0xF0EA4,
+            0x42E4A,
+            0xF164A,
+            0xF1516,
+            0x22936,  # 2100
+        ]
+        # Define range of years covered
+        self.START_YEAR = 1901
+        self.END_YEAR = 2099
+        # The 1st day of the 1st month of the Gregorian calendar is 1901/2/19
+        self.LUNAR_START_DATE = ((1901, 1, 1),)
+        self.SOLAR_START_DATE = date(1901, 2, 19)
+        # The Gregorian date for December 30, 2099 is 2100/2/8
+        self.LUNAR_END_DATE = (2099, 12, 30)
+        self.SOLAR_END_DATE = date(2100, 2, 18)
+
+    @lru_cache()
+    def _get_leap_month(self, lunar_year: int) -> int:
+        """
+        Calculate the leap lunar month in a lunar year.
+
+        :param lunar_year:
+            The lunar year.
+
+        :return:
+            The number of the leap month if one exists in the year, otherwise
+            15.
+        """
+        return (
+            self.G_LUNAR_MONTH_DAYS[lunar_year - self.START_YEAR] >> 16
+        ) & 0x0F
+
+    def _lunar_month_days(self, lunar_year: int, lunar_month: int) -> int:
+        """
+        Calculate the number of days in a lunar month.
+
+        :param lunar_year:
+            The lunar year.
+
+        :param lunar_month:
+            The lunar month of the lunar year.
+
+        :return:
+            The number of days in the lunar month.
+        """
+        return 29 + (
+            (
+                self.G_LUNAR_MONTH_DAYS[lunar_year - self.START_YEAR]
+                >> lunar_month
+            )
+            & 0x01
+        )
+
+    def _lunar_year_days(self, year: int) -> int:
+        """
+        Calculate the number of days in a lunar year.
+
+        :param year:
+            The lunar year.
+
+        :return:
+            The number of days in the lunar year.
+        """
+        days = 0
+        months_day = self.G_LUNAR_MONTH_DAYS[year - self.START_YEAR]
+        for i in range(1, 13 if self._get_leap_month(year) == 0x0F else 14):
+            day = 29 + ((months_day >> i) & 0x01)
+            days += day
+        return days
+
+    @lru_cache()
+    def _span_days(self, year: int) -> int:
+        """
+        Calculate the number of days elapsed since self.SOLAR_START_DATE to the
+        beginning of the year.
+
+        :param year:
+            The year.
+
+        :return:
+             The number of days since self.SOLAR_START_DATE.
+        """
+        span_days = 0
+        for y in range(self.START_YEAR, year):
+            span_days += self._lunar_year_days(y)
+        return span_days
+
+    def lunar_n_y_date(self, year: int) -> date:
+        """
+        Calculate the Gregorian date of Chinese Lunar New Year.
+
+        This is a faster implementation than calling
+        ``lunar_to_gre(year, 1, 1)``.
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            The Gregorian date of Chinese Lunar New Year.
+        """
+        # The Chinese calendar defines the lunar month containing the winter
+        # solstice as the eleventh month, which means that Chinese New Year
+        # usually falls on the second new moon after the winter solstice
+        # (rarely the third if an intercalary month intervenes). In more
+        # than 96 percent of the years, Chinese New Year's Day is the closest
+        # date to a new moon to lichun (Chinese: 立春; "start of spring") on 4
+        # or 5 February, and the first new moon after dahan (Chinese: 大寒;
+        # "major cold"). In the Gregorian calendar, the Chinese New Year begins
+        # at the new moon that falls between 21 January and 20 February.
+
+        span_days = self._span_days(year)
+        # Always in first month (by definition)
+        # leap_month = self._get_leap_month(year)
+        # for m in range(1, 1 + (1 > leap_month)):
+        #     span_days += self._lunar_month_days(year, m)
+        return self.SOLAR_START_DATE + td(days=span_days)
+
+    def lunar_to_gre(
+        self, year: int, month: int, day: int, leap: bool = True
+    ) -> date:
+        """
+        Calculate the Gregorian date of a Chinese lunar day and month in a
+        given Gregorian year.
+
+        :param year:
+            The Gregorian year.
+
+        :param year:
+            The Chinese lunar month.
+
+        :param year:
+            The Chinese lunar day.
+
+        :return:
+            The Gregorian date.
+        """
+        span_days = self._span_days(year)
+        leap_month = self._get_leap_month(year) if leap else 15
+        for m in range(1, month + (month > leap_month)):
+            span_days += self._lunar_month_days(year, m)
+        span_days += day - 1
+        return self.SOLAR_START_DATE + td(days=span_days)
+
+    def vesak_date(self, year: int) -> date:
+        """
+        Calculate the estimated Gregorian date of Vesak for Thailand, Laos,
+        Singapore and Indonesia, corresponding to the fourteenth day of the
+        fourth month in the Chinese lunar calendar. See `Wikipedia
+        <https://en.wikipedia.org/wiki/Vesak#Dates_of_observance>`__.
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Vesak (14th day of 4th month of the
+            lunar calendar).
+        """
+        span_days = self._span_days(year)
+        leap_month = self._get_leap_month(year)
+        for m in range(1, 4 + (4 > leap_month)):
+            span_days += self._lunar_month_days(year, m)
+        span_days += 14
+        return self.SOLAR_START_DATE + td(days=span_days)
+
+    def vesak_may_date(self, year: int) -> date:
+        """
+        Calculate the estimated Gregorian date of Vesak for Sri Lanka, Nepal,
+        India, Bangladesh and Malaysia, corresponding to the day of the
+        first full moon in May in the Gregorian calendar. See `Wikipedia
+        <https://en.wikipedia.org/wiki/Vesak#Dates_of_observance>`__.
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Vesak (first full moon in May).
+        """
+        span_days = self._span_days(year)
+        vesak_may_date = self.SOLAR_START_DATE + td(days=span_days + 14)
+        m = 1
+        while vesak_may_date.month < 5:
+            vesak_may_date += td(days=self._lunar_month_days(year, m))
+            m += 1
+        return vesak_may_date
+
+    def s_diwali_date(self, year: int) -> date:
+        """
+        Calculate the estimated Gregorian date of Southern India (Tamil)
+        Diwali.
+
+        Defined as the date of Amāvásyā (new moon) of Kārttikai, which
+        corresponds with the months of November or December in the Gregorian
+        calendar. See `Wikipedia <https://en.wikipedia.org/wiki/Diwali>`__.
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Southern India (Tamil) Diwali.
+        """
+        span_days = self._span_days(year)
+        leap_month = self._get_leap_month(year)
+        for m in range(1, 10 + (10 > leap_month)):
+            span_days += self._lunar_month_days(year, m)
+        span_days -= 2
+        return self.SOLAR_START_DATE + td(days=span_days)
+
+    def thaipusam_date(self, year: int) -> date:
+        """
+        Calculate the estimated Gregorian date of Thaipusam (Tamil).
+
+        Defined as the date of the full moon in the Tamil month of Thai, which
+        corresponds with the months of January or February in the Gregorian
+        calendar. See `Wikipedia <https://en.wikipedia.org/wiki/Thaipusam>`__.
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Thaipusam (Tamil).
+        """
+        span_days = self._span_days(year)
+        leap_month = self._get_leap_month(year)
+        for m in range(1, 1 + (leap_month <= 6)):
+            span_days += self._lunar_month_days(year, m)
+        span_days -= 15
+        return self.SOLAR_START_DATE + td(days=span_days)
+
+
+class _ThaiLuniSolar:
+    """
+    ** Thai Lunar Calendar Holidays only work from 1941 (B.E. 2484) onwards
+       until 2057 (B.E. 2600) as we only have Thai year-type data for
+       cross-checking until then.
+
+    So here are the basics of the Thai Lunar Calendar
+        3-year types for calendar intercalation:
+            - Pakatimat (Normal Year):
+                    consist of 12 months, has 354 days.
+            - Athikawan (Extra-Day Year): a
+                    add a day to the 7th month of the year, has 355 days
+                    for the synodic month correction.
+            - Athikamat (Extra-Month Year):
+                    we have the 8th month twice, has 384 days for the
+                    sidereal year correction.
+
+        Each month either has 30 (Even months) or 29 (Odd months)
+            - The waxing phase has 15 days until Full Moon and waning
+                phase 14 (Odd Months)/15 (Even Months/
+                Month 7 of Athikawan years) days for the New Moon.
+            - The second "Month 8" for Athikamat years is called
+                "Month 8.8", with all observed holy days delayed from
+                the usual calendar by 1 month.
+
+    List of public holidays dependent on the Thai Lunar Calendar:
+        - Magha Puja/Makha Bucha:
+                15th Waxing Day (Full Moon) of Month 3
+                (On Month 4 for Athikamat Years).
+        - Royal Ploughing Ceremony:
+                Based on this, though Court Astrologer picks the
+                auspicious dates, which sadly don't fall into a
+                predictable pattern; see its specific section below.
+        - Vesak/Visakha Bucha:
+                15th Waxing Day (Full Moon) of Month 6
+                (On Month 7 for Athikamat Years).
+        - Asalha Puja/Asarnha Bucha:
+                15th Waxing Day (Full Moon) of Month 8
+                (On Month 8/8 for Athikamat Years).
+        - Buddhist Lent Day/Wan Khao Phansa:
+                1st Waning Day of Month 8
+                (On Month 8/8 for Athikamat Years).
+
+    Other Buddhist date on Thai Lunar Calendar:
+        - Buddha's Cremation Day/Atthami Bucha
+                8th Waning Day of  Month 6
+                (On Month 7 for Athikamat Years).
+        - End of Buddhist Lent Day/Ok Phansa:
+                15th Waxing Day (Full Moon) of Month 11
+
+    The following code is based on Ninenik Narkdee's PHP implementation,
+    and we're thankful for his work.
+
+    Please avoid touching the Athikawan and Athikamat declaration array
+    at all costs unless you can find sources for them somewhere for 2057++
+
+    Sources: (Ninenik.com 's wbm) http://tiny.cc/wa_ninenik_thluncal_php
+             https://www.myhora.com/ปฏิทิน/ปฏิทิน-พ.ศ.2560.aspx
+
+    Usage example:
+
+    >>> from holidays.utils import _ThaiLuniSolar
+    >>> thls = _ThaiLuniSolar()
+    >>> print(thls.visakha_bucha_date(2010))
+    2010-05-28
+    """
+
+    # Athikawan (Extra-Day Year) list goes from 1941-2057 C.E.
+    # Copied off from 1757-2057 (B.E. 2300-2600) Thai Lunar Calendar
+    ATHIKAWAN_YEARS_GREGORIAN = {
+        1945,
+        1949,
+        1952,
+        1957,
+        1963,
+        1970,
+        1973,
+        1979,
+        1987,
+        1990,
+        1997,
+        2000,
+        2006,
+        2009,
+        2016,
+        2020,
+        2025,
+        2032,
+        2035,
+        2043,
+        2046,
+        2052,
+    }
+
+    # Athikamat (Extra-Month Year) list goes from 1941-2057 C.E.:
+    # Copied off from 1757-2057 (B.E. 2300-2600) Thai Lunar Calendar
+    # Approx formula as follows: (common_era-78)-0.45222)%2.7118886 < 1
+    ATHIKAMAT_YEARS_GREGORIAN = {
+        1942,
+        1944,
+        1947,
+        1950,
+        1953,
+        1956,
+        1958,
+        1961,
+        1964,
+        1966,
+        1969,
+        1972,
+        1975,
+        1977,
+        1980,
+        1983,
+        1985,
+        1988,
+        1991,
+        1994,
+        1996,
+        1999,
+        2002,
+        2004,
+        2007,
+        2010,
+        2012,
+        2015,
+        2018,
+        2021,
+        2023,
+        2026,
+        2029,
+        2031,
+        2034,
+        2037,
+        2040,
+        2042,
+        2045,
+        2048,
+        2050,
+        2053,
+        2056,
+    }
+
+    # While Buddhist Holy Days have been observed since the 1900s
+    #   Due to the calendar changes in 1941 (B.E. 2484) and that
+    #   our array only goes up to B.E. 2600; We'll thus only populate
+    #   the data for 1941-2057 (B.E. 2484-2600).
+    # Sources: หนังสือเวียนกรมการปกครอง กระทรวงมหาดไทย มท 0310.1/ว4 5 ก.พ. 2539
+    START_DATE = date(1940, 11, 30)
+    START_YEAR = 1941
+    END_YEAR = 2057
+
+    @lru_cache()
+    def _get_start_date(self, year: int) -> Optional[date]:
+        """
+        Calculate the start date of that particular Thai Lunar Calendar Year.
+        This usually falls in November or December of the previous Gregorian
+        year in question. Should the year be outside of working scope
+        (1941-2057: B.E 2484-2600), this will returns None instead.
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+             The start date of Thai Lunar Calendar for a Gregorian year.
+        """
+        if year < _ThaiLuniSolar.START_YEAR or year > _ThaiLuniSolar.END_YEAR:
+            return None
+
+        iter_start_date = _ThaiLuniSolar.START_DATE
+        iter_start_year = _ThaiLuniSolar.START_YEAR
+
+        while iter_start_year < year:
+            if iter_start_year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN:
+                delta_days = 384
+            elif iter_start_year in _ThaiLuniSolar.ATHIKAWAN_YEARS_GREGORIAN:
+                delta_days = 355
+            else:
+                delta_days = 354
+            iter_start_date += td(days=delta_days)
+            iter_start_year += 1
+        return iter_start_date
+
+    def makha_bucha_date(self, year: int) -> Optional[date]:
+        """
+        Calculate the estimated Gregorian date of Makha Bucha.
+        If the Gregorian year input is invalud, this will outputs None instead.
+
+        Also known as "Magha Puja". This concides with
+        the 15th Waxing Day of Month 3 in Thai Lunar Calendar,
+        or Month 4 in Athikamat years.
+
+        To calculate, we use use the following time delta:
+        - Athikamat: 15th Waxing Day of Month 4
+                     or 29[1] + 30[2] + 29[3] + 15[4] -1 = 102
+        - Athikawan: 15th Waxing Day of Month 3
+                     or 29[1] + 30[2] + 15[3] -1 = 73
+        - Pakatimat: 15th Waxing Day of Month 3
+                     or 29[1] + 30[2] + 15[3] -1 = 73
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Makha Bucha.
+        """
+        start_date = self._get_start_date(year)
+        if not start_date:
+            return None
+
+        return start_date + td(
+            days=+102
+            if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN
+            else +73
+        )
+
+    def visakha_bucha_date(self, year: int) -> Optional[date]:
+        """
+        Calculate the estimated Gregorian date of Visakha Bucha.
+        If the Gregorian year input is invalud, this will outputs None instead.
+
+        Also known as "Vesak" and "Buddha Day". This concides with
+        the 15th Waxing Day of Month 6 in Thai Lunar Calendar,
+        or Month 7 in Athikamat years.
+
+        To calculate, we use use the following time delta:
+        - Athikamat: 15th Waxing Day of Month 6
+                     or 177[1-6] + 15[7] -1 = 191
+        - Athikawan: 15th Waxing Day of Month 6
+                     or 147[1-5] + 15[6] -1 = 161
+        - Pakatimat: 15th Waxing Day of Month 6
+                     or 147[1-5] + 15[6] -1 = 161
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Visakha Bucha.
+        """
+        start_date = self._get_start_date(year)
+        if not start_date:
+            return None
+
+        return start_date + td(
+            days=+191
+            if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN
+            else +161
+        )
+
+    def atthami_bucha_date(self, year: int) -> Optional[date]:
+        """
+        Calculate the estimated Gregorian date of Atthami Bucha.
+        If the Gregorian year input is invalud, this will outputs None instead.
+
+        Also known as "Buddha's Cremation Day". This concides with
+        the 8th Waning Day of Month 6 in Thai Lunar Calendar,
+        or Month 7 in Athikamat years.
+
+        To calculate, we use use the following time delta:
+        - Athikamat: 8th Waning Day of  Month 7
+                    or 177[1-6] + 23[7] -1 = 199
+        - Athikawan: 8th Waning Day of  Month 6
+                     or 147[1-5] + 23[6] -1 = 169
+        - Pakatimat: 8th Waning Day of  Month 6
+                    or 147[1-5] + 23[6] -1 = 169
+        - Or as in simpler terms: "Visakha Bucha" +8
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Atthami Bucha.
+        """
+        start_date = self._get_start_date(year)
+        if not start_date:
+            return None
+
+        return start_date + td(
+            days=+199
+            if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN
+            else +169
+        )
+
+    def asarnha_bucha_date(self, year: int) -> Optional[date]:
+        """
+        Calculate the estimated Gregorian date of Asarnha Bucha.
+        If the Gregorian year input is invalud, this will outputs None instead.
+
+        Also known as "Asalha Puja". This concides with
+        the 15th Waxing Day of Month 8 in Thai Lunar Calendar,
+        or Month 8.8 in Athikamat years.
+
+        To calculate, we use use the following time delta:
+        - Athikamat: 15th Waxing Day of Month 8/8
+                     or 177[1-6] + 29[7] + 30[8] + 15[8.8] -1 = 250
+        - Athikawan: 15th Waxing Day of Month 8
+                     or 177[1-6] + 30[7] + 15[8] -1 = 221
+        - Pakatimat: 15th Waxing Day of Month 8
+                     or 177[1-6] + 29[7] + 15[8] -1 = 220
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Asarnha Bucha.
+        """
+        start_date = self._get_start_date(year)
+        if not start_date:
+            return None
+
+        if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN:
+            delta_days = 250
+        elif year in _ThaiLuniSolar.ATHIKAWAN_YEARS_GREGORIAN:
+            delta_days = 221
+        else:
+            delta_days = 220
+        return start_date + td(days=delta_days)
+
+    def khao_phansa_date(self, year: int) -> Optional[date]:
+        """
+        Calculate the estimated Gregorian date of Khao Phansa.
+        If the Gregorian year input is invalud, this will outputs None instead.
+
+        Also known as "(Start of) Buddhist Lent" and "Start of Vassa".
+        This concides with the 1st Waning Day of Month 8
+        in Thai Lunar Calendar, or Month 8.8 in Athikamat years.
+
+        To calculate, we use use the following time delta:
+        - Athikamat: 1st Waning Day of Month 8.8
+                     or 177[1-6] + 29[7] + 30[8] + 16[8.8] -1 = 251
+        - Athikawan: 1st Waning Day of Month 8 ]
+                     or 177[1-6] + 30[7] + 16[8] -1 = 222
+        - Pakatimat: 1st Waning Day of Month 8
+                     or 177[1-6] + 29[7] + 16[8] -1 = 221
+        - Or as in simpler terms: "Asarnha Bucha" +1
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Khao Phansa.
+        """
+        start_date = self._get_start_date(year)
+        if not start_date:
+            return None
+
+        if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN:
+            delta_days = 251
+        elif year in _ThaiLuniSolar.ATHIKAWAN_YEARS_GREGORIAN:
+            delta_days = 222
+        else:
+            delta_days = 221
+        return start_date + td(days=delta_days)
+
+    def ok_phansa_date(self, year: int) -> Optional[date]:
+        """
+        Calculate the estimated Gregorian date of Ok Phansa
+        If the Gregorian year input is invalud, this will outputs None instead.
+
+        Also known as "End of Buddhist Lent" and "End of Vassa".
+        This concides with the 15th Waxing Day of Month 11
+        in Thai Lunar Calendar.
+
+        To calculate, we use use the following time delta:
+        - Athikamat: 15th Waxing Day of Month 11
+                     or 295[1-10] + 30[8.8] + 15[11] -1 = 339
+        - Athikawan: 15th Waxing Day of Month 11
+                     or 295[1-10] + 1[7] + 15[11] -1 = 310
+        - Pakatimat: 15th Waxing Day of Month 11
+                     or 295[1-10] + 15[11] -1 = 309
+
+        :param year:
+            The Gregorian year.
+
+        :return:
+            Estimated Gregorian date of Ok Phansa.
+        """
+        start_date = self._get_start_date(year)
+        if not start_date:
+            return None
+
+        if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN:
+            delta_days = 339
+        elif year in _ThaiLuniSolar.ATHIKAWAN_YEARS_GREGORIAN:
+            delta_days = 310
+        else:
+            delta_days = 309
+        return start_date + td(days=delta_days)
diff --git a/holidays/countries/albania.py b/holidays/countries/albania.py
index 9ba54df24..dd1c655d3 100644
--- a/holidays/countries/albania.py
+++ b/holidays/countries/albania.py
@@ -14,9 +14,9 @@
 
 from dateutil.easter import EASTER_ORTHODOX, easter
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, MAY, SEP, OCT, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Albania(HolidayBase):
diff --git a/holidays/countries/argentina.py b/holidays/countries/argentina.py
index 76ec0855a..522c95c57 100644
--- a/holidays/countries/argentina.py
+++ b/holidays/countries/argentina.py
@@ -11,144 +11,339 @@
 
 from datetime import date
 from datetime import timedelta as td
+from gettext import gettext as tr
 
 from dateutil.easter import easter
 
-from holidays.constants import JAN, MAR, APR, MAY, JUN, JUL, AUG, OCT, NOV, DEC
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
+from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
+from holidays.constants import OCT, NOV, DEC, MON
 from holidays.holiday_base import HolidayBase
 
-# from dateutil.rrule import weekday
-
 
 class Argentina(HolidayBase):
     """
-    https://www.argentina.gob.ar/interior/feriados
-    https://es.wikipedia.org/wiki/Anexo:D%C3%ADas_feriados_en_Argentina
-    http://servicios.lanacion.com.ar/feriados
-    https://www.clarin.com/feriados/
+    A subclass of :py:class:`HolidayBase` representing public holidays
+    in Argentina.
+
+
+    References:
+
+    - Based on:
+        https://es.wikipedia.org/wiki/Anexo:D%C3%ADas_feriados_en_Argentina
+    - [Ley 24455] Belgrano and San Martin Day as third Monday
+    - [Ley 27399] - For 2018++
+        https://www.argentina.gob.ar/normativa/nacional/ley-27399-281835/texto
+    - [Decreto 1585/2010] - 2011-2013 Bridge Holidays, Movable Holidays Law
+    - [Decreto 1768/2013] - 2014-2016 Bridge Holidays
+    - [Decretos 52-80-923/2017] - 2017-2019 Bridge Holidays
+    - [Decreto 717/2019] - 2020 Bridge Holidays
+    - [Decreto 297/2020] - Veteran Day moved due to Covid-19
+    - [Decreto 947/2020] - 2021 Bridge Holidays
+    - [Decreto 789/2021] - 2022 Bridge Holidays
+    - [Decreto 764/2022] - 2023 Bridge Holidays
+    - [Always Update Calendar Year Link]
+        https://www.argentina.gob.ar/interior/feriados
+        http://servicios.lanacion.com.ar/feriados
+        https://www.clarin.com/feriados/
+    - [Specific Calendar Year]
+        https://www.lanacion.com.ar/feriados/2024/
+        https://www.argentina.gob.ar/interior/feriados-nacionales-2023
+        https://www.argentina.gob.ar/interior/feriados-nacionales-2022
+        https://www.argentina.gob.ar/interior/feriados-nacionales-2021
+        https://www.argentina.gob.ar/interior/feriados-nacionales-2020
+        https://www.cultura.gob.ar/feriados-2019-en-argentina_7326/
+        https://servicios.lanacion.com.ar/app-mobile/feriados/2019
+        https://servicios.lanacion.com.ar/app-mobile/feriados/2018
+        https://servicios.lanacion.com.ar/app-mobile/feriados/2017
+        https://servicios.lanacion.com.ar/app-mobile/feriados/2016
+        https://servicios.lanacion.com.ar/app-mobile/feriados/2015
     """
 
     country = "AR"
     default_language = "es"
 
+    # Special Bridge Holidays are given upto 3 days a year
+    # as long as it's declared 50 days before calendar year's end
+    # There's no Bridge Holidays declared in 2017
+
+    arg_bridge_public_holiday = tr("Feriado con fines turísticos")
+
+    # Special Cases
+
+    bicentennial_national_flag = tr(
+        "Bicentenario de la creación y primera jura de la bandera nacional"
+    )
+    bicentennial_battle_tucuman = tr("Bicentenario de la Batalla de Tucumán")
+    bicentennial_assembly_1813 = tr(
+        "Bicentenario de la sesión inaugural "
+        "de la Asamblea Nacional Constituyente del año 1813"
+    )
+    bicentennial_battle_salta = tr("Bicentenario de la Batalla de Salta")
+    national_census_2022 = tr("Censo nacional 2022")
+
+    special_holidays = {
+        2011: (
+            (MAR, 25, arg_bridge_public_holiday),
+            (DEC, 9, arg_bridge_public_holiday),
+        ),
+        2012: (
+            (FEB, 27, bicentennial_national_flag),
+            (APR, 30, arg_bridge_public_holiday),
+            (SEP, 24, bicentennial_battle_tucuman),
+            (DEC, 24, arg_bridge_public_holiday),
+        ),
+        2013: (
+            (JAN, 31, bicentennial_assembly_1813),
+            (FEB, 20, bicentennial_battle_salta),
+            (APR, 1, arg_bridge_public_holiday),
+            (JUN, 21, arg_bridge_public_holiday),
+        ),
+        2014: (
+            (MAY, 2, arg_bridge_public_holiday),
+            (DEC, 26, arg_bridge_public_holiday),
+        ),
+        2015: (
+            (MAR, 23, arg_bridge_public_holiday),
+            (DEC, 7, arg_bridge_public_holiday),
+        ),
+        2016: (
+            (JUL, 8, arg_bridge_public_holiday),
+            (DEC, 9, arg_bridge_public_holiday),
+        ),
+        2018: (
+            (APR, 30, arg_bridge_public_holiday),
+            (DEC, 24, arg_bridge_public_holiday),
+            (DEC, 31, arg_bridge_public_holiday),
+        ),
+        2019: (
+            (JUL, 8, arg_bridge_public_holiday),
+            (AUG, 19, arg_bridge_public_holiday),
+            (OCT, 14, arg_bridge_public_holiday),
+        ),
+        2020: (
+            (MAR, 23, arg_bridge_public_holiday),
+            (JUL, 10, arg_bridge_public_holiday),
+            (DEC, 7, arg_bridge_public_holiday),
+        ),
+        2021: (
+            (MAY, 24, arg_bridge_public_holiday),
+            (OCT, 8, arg_bridge_public_holiday),
+            (NOV, 22, arg_bridge_public_holiday),
+        ),
+        2022: (
+            (MAY, 18, national_census_2022),
+            (OCT, 7, arg_bridge_public_holiday),
+            (NOV, 21, arg_bridge_public_holiday),
+            (DEC, 9, arg_bridge_public_holiday),
+        ),
+        2023: (
+            (MAY, 26, arg_bridge_public_holiday),
+            (JUN, 19, arg_bridge_public_holiday),
+            (OCT, 13, arg_bridge_public_holiday),
+        ),
+    }
+
     def _populate(self, year):
+        def _add_movable(hol_date: date, hol_name: str) -> None:
+            """
+            !!! Movable Holidays Law !!!
+
+            - Decreto 1584/2010: 2010-11-03
+                - AUG 17, OCT 12, NOV 20 Holidays will always be on MON
+            - Decreto 52/2017: 2017-01-23 (Reconfirmed in Ley 27399)
+                - If TUE/WED - observed on previous MON
+                - If THU/FRI - observed on next MON
+            """
+            if self.observed:
+                if self._is_tuesday(hol_date) or self._is_wednesday(hol_date):
+                    hol_date = _get_nth_weekday_from(-1, MON, hol_date)
+                    hol_name = self.tr("%s (Observado)") % hol_name
+                elif self._is_thursday(hol_date) or self._is_friday(hol_date):
+                    hol_date = _get_nth_weekday_from(1, MON, hol_date)
+                    hol_name = self.tr("%s (Observado)") % hol_name
+            self[hol_date] = hol_name
+
         super()._populate(year)
 
-        # New Year's Day
-        if not self.observed and self._is_weekend(year, JAN, 1):
-            pass
-        else:
-            self[date(year, JAN, 1)] = self.tr("Año Nuevo")
+        # Fixed Holidays
 
         easter_date = easter(year)
-        # Carnival days
-        name = self.tr("Día de Carnaval")
-        self[easter_date + td(days=-48)] = name
-        self[easter_date + td(days=-47)] = name
 
-        # Memory's National Day for the Truth and Justice
-        name = self.tr(
-            "Día Nacional de la Memoria por la Verdad y la Justicia"
-        )
+        # New Year's Day.
+        # Status: In-Use.
+
+        self[date(year, JAN, 1)] = self.tr("Año Nuevo")
 
-        if not self.observed and self._is_weekend(year, MAR, 24):
-            pass
-        else:
-            self[date(year, MAR, 24)] = name
-
-        # Holy Week
-        name_thu = self.tr("Semana Santa (Jueves Santo)")
-        name_fri = self.tr("Semana Santa (Viernes Santo)")
-        name_easter = self.tr("Día de Pascuas")
-
-        self[easter_date + td(days=-3)] = name_thu
-        self[easter_date + td(days=-2)] = name_fri
-
-        if not self.observed and self._is_weekend(easter_date):
-            pass
-        else:
-            self[easter_date] = name_easter
-
-        # Veterans Day and the Fallen in the Malvinas War
-        if not self.observed and self._is_weekend(year, APR, 2):
-            pass
-        else:
-            self[date(year, APR, 2)] = self.tr(
-                "Día del Veterano y de los Caidos en la Guerra de Malvinas"
+        # Carnival days.
+        # Status: In-Use.
+        # Started in 1956, abandoned in 1976.
+        # Restarted in 2011 via Decreto 1584/2010.
+
+        if 1956 <= year <= 1975 or year >= 2011:
+            name = self.tr("Día de Carnaval")
+            self[easter_date + td(days=-48)] = name
+            self[easter_date + td(days=-47)] = name
+
+        # Memory's National Day for the Truth and Justice.
+        # Status: In-Use
+        # Started in 2006, nearly reclassified as Movable Holidays in 2017
+
+        if year >= 2006:
+            self[date(year, MAR, 24)] = self.tr(
+                "Día Nacional de la Memoria por la Verdad y la Justicia"
             )
 
-        # Labor Day
-        name = self.tr("Día del Trabajo")
-        if not self.observed and self._is_weekend(year, MAY, 1):
-            pass
-        else:
-            self[date(year, MAY, 1)] = name
-
-        # May Revolution Day
-        name = self.tr("Día de la Revolución de Mayo")
-        if not self.observed and self._is_weekend(year, MAY, 25):
-            pass
-        else:
-            self[date(year, MAY, 25)] = name
-
-        # Day Pass to the Immortality of General Martín Miguel de Güemes.
-        name = self.tr(
-            "Día Pase a la Inmortalidad del General Martín Miguel de Güemes"
-        )
-        if not self.observed and self._is_weekend(year, JUN, 17):
-            pass
-        else:
-            self[date(year, JUN, 17)] = name
+        # Veterans Day and the Fallen in the Malvinas War.
+        # Status: In-Use.
+        # Started in 1993 as War Veterans Day via Ley 24160.
+        # Merged in 2001, confirmed as Fixed Holiday in 2006.
+        # Superceded "Day of Argentine Sovereignty over the Malvinas".
+        # Got moved temporary in 2020 (Decreto 297/2020).
+
+        if year >= 1993:
+            self[
+                date(year, MAR, 31) if year == 2020 else date(year, APR, 2)
+            ] = (
+                self.tr("Día del Veterano de Guerra")
+                if year <= 2000
+                else self.tr(
+                    "Día del Veterano y de los Caidos en la Guerra de Malvinas"
+                )
+            )
+
+        # Good Friday.
+        # Status: In-Use.
+
+        self[easter_date + td(days=-2)] = self.tr("Viernes Santo")
+
+        # Labor Day.
+        # Status: In-Use.
+        # First observed as national holiday in Argentina in 1930.
+
+        if year >= 1930:
+            self[date(year, MAY, 1)] = self.tr("Día del Trabajo")
+
+        # May Revolution Day.
+        # Status: In-Use.
+        # Started in 1813, confirmed as fixed holidays in 1976 via Ley 21329.
+
+        if year >= 1813:
+            self[date(year, MAY, 25)] = self.tr("Día de la Revolución de Mayo")
+
+        # Day of Argentine Sovereignty over the Malvinas.
+        # Status: Defunct.
+        # Started in 1983 on April 2, moved to June 10 in Decreto 901/1984.
+        # Abandoned in 2001.
+        # Superceded by "Veterans Day and the Fallen in the Malvinas War".
+
+        if 1983 <= year <= 2000:
+            self[
+                date(year, APR, 2) if year == 1983 else date(year, JUN, 10)
+            ] = self.tr(
+                "Día de los Derechos Argentinos sobre las Islas Malvinas, "
+                "Sandwich y del Atlántico Sur"
+            )
+
+        # Day Pass to the Immortality of General Don Manuel Belgrano.
+        # Also called "National Flag Day" (Día de la Bandera Nacional).
+        # Status: In-Use.
+        # Started in 1938 via Ley 12361 as Fixed Holiday.
+        # Set as 3rd MON of JUN via Ley 24455 in Dec 1994.
+        # Made Fixed Holiday again in 2011.
+
+        if year >= 1938:
+            self[
+                _get_nth_weekday_of_month(3, MON, JUN, year)
+                if 1995 <= year <= 2010
+                else date(year, JUN, 20)
+            ] = self.tr(
+                "Paso a la Inmortalidad del General Don Manuel Belgrano"
+            )
+
+        # Independence Day.
+        # Status: In-Use.
+        # Started in 1816.
+
+        if year >= 1816:
+            self[date(year, JUL, 9)] = self.tr("Día de la Independencia")
+
+        # Immaculate Conception.
+        # Status: In-Use.
+
+        self[date(year, DEC, 8)] = self.tr("Inmaculada Concepción de María")
+
+        # Christmas.
+        # Status: In-Use.
+
+        self[date(year, DEC, 25)] = self.tr("Navidad")
+
+        # Movable Holidays
+
+        # Day Pass to the Immortality of General Don Martín Miguel de Güemes.
+        # Status: In-Use.
+        # Started in 2014 for Salta, 2016 for the whole country via Ley 27258.
+
+        if year >= 2016:
+            dt = date(year, JUN, 17)
+            name = self.tr(
+                "Paso a la Inmortalidad del General Don Martín Miguel "
+                "de Güemes"
+            )
+            # If Jun 17 is Friday, then it should move to Mon, Jun 20
+            # but Jun 20 is Gen. Belgrano holiday
+            if self._is_friday(dt):
+                self[dt] = name
+            else:
+                _add_movable(dt, name)
+
+        # Day Pass to the Immortality of General José de San Martin.
+        # Status: In-Use.
+        # Started in 1938 via Ley 12387 on Aug 17.
+        # Set as 3rd MON of AUG via Ley 24455 in Dec 1994.
+        # Moved to Aug 22 for 2011 (election interfere) via Decreto 521/2011.
 
-        # Day Pass to the Immortality of General D. Manuel Belgrano.
-        name = self.tr(
-            "Día Pase a la Inmortalidad del General D. Manuel Belgrano"
-        )
-        if not self.observed and self._is_weekend(year, JUN, 20):
-            pass
-        else:
-            self[date(year, JUN, 20)] = name
-
-        # Independence Day
-        name = self.tr("Día de la Independencia")
-        if not self.observed and self._is_weekend(year, JUL, 9):
-            pass
-        else:
-            self[date(year, JUL, 9)] = name
-
-        # Day Pass to the Immortality of General D. José de San Martin
         name = self.tr(
-            "Día Pase a la Inmortalidad del General D. José de San Martin"
+            "Paso a la Inmortalidad del General Don José de San Martin"
         )
-        if not self.observed and self._is_weekend(year, AUG, 17):
-            pass
-        else:
+
+        if year == 2011:
+            self[date(year, AUG, 22)] = name
+        elif 1938 <= year <= 1994:
             self[date(year, AUG, 17)] = name
+        elif 1995 <= year <= 2010:
+            self[_get_nth_weekday_of_month(3, MON, AUG, year)] = name
+        elif year >= 2012:
+            _add_movable(date(year, AUG, 17), name)
+
+        # Respect for Cultural Diversity Day or Columbus Day.
+        # Status: In-Use.
+        # First started in 1917 for Argentina.
+        # Have its name changed from 2010 onwards.
 
-        # Respect for Cultural Diversity Day or Columbus day
-        if not self.observed and self._is_weekend(year, OCT, 12):
-            pass
-        elif year < 2010:
-            self[date(year, OCT, 12)] = self.tr("Día de la Raza")
-        else:
-            self[date(year, OCT, 12)] = self.tr(
-                "Día del Respeto a la Diversidad Cultural"
+        if year >= 1917:
+            name = (
+                self.tr("Día del Respeto a la Diversidad Cultural")
+                if year >= 2010
+                else self.tr("Día de la Raza")
             )
-        # National Sovereignty Day
-        name = self.tr("Día Nacional de la Soberanía")
-        if not self.observed and self._is_weekend(year, NOV, 20):
-            pass
-        elif year >= 2010:
-            self[date(year, NOV, 20)] = name
+            _add_movable(date(year, OCT, 12), name)
 
-        # Immaculate Conception
-        if not self.observed and self._is_weekend(year, DEC, 8):
-            pass
-        else:
-            self[date(year, DEC, 8)] = self.tr("La Inmaculada Concepción")
+        # National Sovereignty Day.
+        # Status: In-Use.
+        # First observed with no holiday via Ley 20770 in 1974.
+        # Started in 2010.
+        # Moved to Nov 27 for 2015 (election interfere).
+        # Moved to Nov 28 again for 2016.
 
-        # Christmas
-        self[date(year, DEC, 25)] = self.tr("Navidad")
+        name = self.tr("Día de la Soberanía Nacional")
+
+        if year == 2015:
+            self[date(year, NOV, 27)] = name
+        elif year == 2016:
+            self[date(year, NOV, 28)] = name
+        elif year >= 2010:
+            _add_movable(date(year, NOV, 20), name)
 
 
 class AR(Argentina):
diff --git a/holidays/countries/australia.py b/holidays/countries/australia.py
index 0474f8c9c..a0fb370d0 100644
--- a/holidays/countries/australia.py
+++ b/holidays/countries/australia.py
@@ -13,10 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO, TU, WE, FR
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAR, APR, MAY, JUN, AUG, SEP, OCT, NOV, DEC
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
+from holidays.constants import JAN, MAR, APR, MAY, JUN, AUG, SEP, OCT, NOV
+from holidays.constants import DEC, MON, TUE, FRI
 from holidays.holiday_base import HolidayBase
 
 
@@ -57,7 +57,7 @@ def _populate(self, year):
         jan1 = date(year, JAN, 1)
         self[jan1] = name
         if self.observed and self._is_weekend(jan1):
-            self[jan1 + rd(weekday=MO)] = name + " (Observed)"
+            self[_get_nth_weekday_from(1, MON, jan1)] = name + " (Observed)"
 
         # Australia Day
         jan26 = date(year, JAN, 26)
@@ -68,7 +68,9 @@ def _populate(self, year):
                 name = "Australia Day"
             self[jan26] = name
             if self.observed and year >= 1946 and self._is_weekend(jan26):
-                self[jan26 + rd(weekday=MO)] = name + " (Observed)"
+                self[_get_nth_weekday_from(1, MON, jan26)] = (
+                    name + " (Observed)"
+                )
         elif year >= 1888 and self.subdiv != "SA":
             name = "Anniversary Day"
             self[jan26] = name
@@ -78,23 +80,23 @@ def _populate(self, year):
             name = "Adelaide Cup"
             if year >= 2006:
                 # subject to proclamation ?!?!
-                self[date(year, MAR, 1) + rd(weekday=MO(+2))] = name
+                self[_get_nth_weekday_of_month(2, MON, MAR, year)] = name
             else:
-                self[date(year, MAR, 1) + rd(weekday=MO(+3))] = name
+                self[_get_nth_weekday_of_month(3, MON, MAR, year)] = name
 
         # Canberra Day
         # Info from https://www.timeanddate.com/holidays/australia/canberra-day
         # and https://en.wikipedia.org/wiki/Canberra_Day
         if self.subdiv == "ACT" and year >= 1913:
             name = "Canberra Day"
-            if year >= 1913 and year <= 1957:
+            if year <= 1957:
                 self[date(year, MAR, 12)] = name
-            if year >= 1958 and year <= 2007:
-                self[date(year, MAR, 1) + rd(weekday=MO(+3))] = name
-            if year >= 2008 and year != 2012:
-                self[date(year, MAR, 1) + rd(weekday=MO(+2))] = name
-            if year == 2012:
+            elif year <= 2007:
+                self[_get_nth_weekday_of_month(3, MON, MAR, year)] = name
+            elif year == 2012:
                 self[date(year, MAR, 12)] = name
+            else:
+                self[_get_nth_weekday_of_month(2, MON, MAR, year)] = name
 
         # Easter
         easter_date = easter(year)
@@ -115,7 +117,9 @@ def _populate(self, year):
                     "WA",
                     "NT",
                 }:
-                    self[apr25 + rd(weekday=MO)] = name + " (Observed)"
+                    self[_get_nth_weekday_from(1, MON, apr25)] = (
+                        name + " (Observed)"
+                    )
                 elif self._is_sunday(apr25) and self.subdiv in {
                     "ACT",
                     "NT",
@@ -123,7 +127,9 @@ def _populate(self, year):
                     "SA",
                     "WA",
                 }:
-                    self[apr25 + rd(weekday=MO)] = name + " (Observed)"
+                    self[_get_nth_weekday_from(1, MON, apr25)] = (
+                        name + " (Observed)"
+                    )
 
         # Western Australia Day
         if self.subdiv == "WA" and year > 1832:
@@ -131,7 +137,7 @@ def _populate(self, year):
                 name = "Western Australia Day"
             else:
                 name = "Foundation Day"
-            self[date(year, JUN, 1) + rd(weekday=MO(+1))] = name
+            self[_get_nth_weekday_of_month(1, MON, JUN, year)] = name
 
         # Sovereign's Birthday
         if 1952 <= year <= 2022:
@@ -143,17 +149,14 @@ def _populate(self, year):
                 if year == 2012:
                     self[date(year, JUN, 11)] = "Queen's Diamond Jubilee"
                 if year < 2016 and year != 2012:
-                    dt = date(year, JUN, 1) + rd(weekday=MO(+2))
-                    self[dt] = name
+                    self[_get_nth_weekday_of_month(2, MON, JUN, year)] = name
                 else:
-                    dt = date(year, OCT, 1) + rd(weekday=MO)
-                    self[dt] = name
+                    self[_get_nth_weekday_of_month(1, MON, OCT, year)] = name
             elif self.subdiv == "WA":
                 # by proclamation ?!?!
-                self[date(year, OCT, 1) + rd(weekday=MO(-1))] = name
+                self[_get_nth_weekday_from(-1, MON, date(year, OCT, 1))] = name
             elif self.subdiv in {"ACT", "NSW", "NT", "SA", "TAS", "VIC"}:
-                dt = date(year, JUN, 1) + rd(weekday=MO(+2))
-                self[dt] = name
+                self[_get_nth_weekday_of_month(2, MON, JUN, year)] = name
         elif year > 1911:
             self[date(year, JUN, 3)] = name  # George V
         elif year > 1901:
@@ -161,40 +164,37 @@ def _populate(self, year):
 
         # Picnic Day
         if self.subdiv == "NT":
-            name = "Picnic Day"
-            self[date(year, AUG, 1) + rd(weekday=MO)] = name
+            self[_get_nth_weekday_of_month(1, MON, AUG, year)] = "Picnic Day"
 
         # Bank Holiday
-        if self.subdiv == "NSW":
-            if year >= 1912:
-                name = "Bank Holiday"
-                self[date(year, 8, 1) + rd(weekday=MO)] = name
+        if self.subdiv == "NSW" and year >= 1912:
+            self[_get_nth_weekday_of_month(1, MON, AUG, year)] = "Bank Holiday"
 
         # Labour Day
         name = "Labour Day"
         if self.subdiv in {"ACT", "NSW", "SA"}:
-            self[date(year, OCT, 1) + rd(weekday=MO)] = name
+            self[_get_nth_weekday_of_month(1, MON, OCT, year)] = name
         elif self.subdiv == "WA":
-            self[date(year, MAR, 1) + rd(weekday=MO)] = name
+            self[_get_nth_weekday_of_month(1, MON, MAR, year)] = name
         elif self.subdiv == "VIC":
-            self[date(year, MAR, 1) + rd(weekday=MO(+2))] = name
+            self[_get_nth_weekday_of_month(2, MON, MAR, year)] = name
         elif self.subdiv == "QLD":
             if 2013 <= year <= 2015:
-                self[date(year, OCT, 1) + rd(weekday=MO)] = name
+                self[_get_nth_weekday_of_month(1, MON, OCT, year)] = name
             else:
-                self[date(year, MAY, 1) + rd(weekday=MO)] = name
+                self[_get_nth_weekday_of_month(1, MON, MAY, year)] = name
         elif self.subdiv == "NT":
-            name = "May Day"
-            self[date(year, MAY, 1) + rd(weekday=MO)] = name
+            self[_get_nth_weekday_of_month(1, MON, MAY, year)] = "May Day"
         elif self.subdiv == "TAS":
-            name = "Eight Hours Day"
-            self[date(year, MAR, 1) + rd(weekday=MO(+2))] = name
+            self[
+                _get_nth_weekday_of_month(2, MON, MAR, year)
+            ] = "Eight Hours Day"
 
         # Family & Community Day
         if self.subdiv == "ACT":
             name = "Family & Community Day"
             if 2007 <= year <= 2009:
-                self[date(year, NOV, 1) + rd(weekday=TU)] = name
+                self[_get_nth_weekday_of_month(1, TUE, NOV, year)] = name
             elif year == 2010:
                 # first Monday of the September/October school holidays
                 # moved to the second Monday if this falls on Labour day
@@ -217,26 +217,29 @@ def _populate(self, year):
                 self[date(year, SEP, 25)] = name
 
         # Reconciliation Day
-        if self.subdiv == "ACT":
-            name = "Reconciliation Day"
-            if year >= 2018:
-                self[date(year, 5, 27) + rd(weekday=MO)] = name
+        if self.subdiv == "ACT" and year >= 2018:
+            self[
+                _get_nth_weekday_from(1, MON, date(year, MAY, 27))
+            ] = "Reconciliation Day"
 
         if self.subdiv == "VIC":
             # Grand Final Day
+            name = "Grand Final Day"
             if year == 2022:
-                self[date(2022, SEP, 23)] = "Grand Final Day"
+                self[date(2022, SEP, 23)] = name
             elif year == 2020:
                 # Rescheduled due to COVID-19
-                self[date(year, OCT, 23)] = "Grand Final Day"
+                self[date(year, OCT, 23)] = name
             elif year == 2021:
                 # Rescheduled due to COVID-19
-                self[date(year, SEP, 24)] = "Grand Final Day"
+                self[date(year, SEP, 24)] = name
             elif year >= 2015:
-                self[date(year, SEP, 24) + rd(weekday=FR)] = "Grand Final Day"
+                self[_get_nth_weekday_from(1, FRI, date(year, SEP, 24))] = name
 
             # Melbourne Cup
-            self[date(year, NOV, 1) + rd(weekday=TU)] = "Melbourne Cup"
+            self[
+                _get_nth_weekday_of_month(1, TUE, NOV, year)
+            ] = "Melbourne Cup"
 
         # The Royal Queensland Show (Ekka)
         # The Show starts on the first Friday of August - providing this is
@@ -250,7 +253,8 @@ def _populate(self, year):
             self[
                 ekka_dates.get(
                     year,
-                    date(year, AUG, 5) + rd(weekday=FR) + rd(weekday=WE),
+                    _get_nth_weekday_from(1, FRI, date(year, AUG, 5))
+                    + td(days=+5),
                 )
             ] = "The Royal Queensland Show"
 
diff --git a/holidays/countries/azerbaijan.py b/holidays/countries/azerbaijan.py
index fd0fe3f64..f969ef8b4 100644
--- a/holidays/countries/azerbaijan.py
+++ b/holidays/countries/azerbaijan.py
@@ -11,11 +11,12 @@
 
 from datetime import date
 from datetime import timedelta as td
+from typing import Dict, List
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT
 from holidays.constants import NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Azerbaijan(HolidayBase):
@@ -26,54 +27,52 @@ class Azerbaijan(HolidayBase):
     country = "AZ"
 
     def _populate(self, year: int) -> None:
-        def _add_observed(hol_date: date, hol_name: str) -> None:
-            next_workday = hol_date + td(days=+1)
-            while next_workday.year == year and (
-                self._is_weekend(next_workday) or self.get(next_workday)
-            ):
-                next_workday += td(days=+1)
-            _add_holiday(next_workday, f"{hol_name} (Observed)")
-
-        def _add_holiday(hol_date: date, hol_name: str) -> None:
-            if hol_date.year == year:
-                self[hol_date] = hol_name
+        def collect_holiday(hol_date: date, hol_name: str) -> None:
+            if hol_date in holiday_date_names_mapping:
+                holiday_date_names_mapping[hol_date].append(hol_name)
+            else:
+                holiday_date_names_mapping[hol_date] = [hol_name]
 
         if year <= 1989:
             return None
 
         super()._populate(year)
 
+        holiday_date_names_mapping: Dict[date, List[str]] = {}
+
         # New Year
         name = "New Year's Day"
-        self[date(year, JAN, 1)] = name
+        collect_holiday(date(year, JAN, 1), name)
         if year >= 2006:
-            self[date(year, JAN, 2)] = name
+            collect_holiday(date(year, JAN, 2), name)
 
-        # Black January
+        # Black January (without extending)
         if year >= 2000:
             self[date(year, JAN, 20)] = "Black January"
 
         # International Women's Day
-        self[date(year, MAR, 8)] = "International Women's Day"
+        collect_holiday(date(year, MAR, 8), "International Women's Day")
 
         # Novruz
         if year >= 2007:
             for i in range(20, 25):
-                self[date(year, MAR, i)] = "Novruz"
+                collect_holiday(date(year, MAR, i), "Novruz")
 
         # Victory Day
-        self[date(year, MAY, 9)] = "Victory Day over Fascism"
+        collect_holiday(date(year, MAY, 9), "Victory Day over Fascism")
 
         # Republic Day
         if year >= 1992:
-            name = "Independence Day" if year >= 2021 else "Republic Day"
-            self[date(year, MAY, 28)] = name
+            collect_holiday(
+                date(year, MAY, 28),
+                "Independence Day" if year >= 2021 else "Republic Day",
+            )
 
         # National Salvation Day
         if year >= 1997:
-            self[date(year, JUN, 15)] = "National Salvation Day"
+            collect_holiday(date(year, JUN, 15), "National Salvation Day")
 
-        # Memorial Day
+        # Memorial Day (without extending)
         if year >= 2021:
             self[date(year, SEP, 27)] = "Memorial Day"
 
@@ -83,28 +82,25 @@ def _add_holiday(hol_date: date, hol_name: str) -> None:
             if year <= 1997:
                 self[date(year, OCT, 9)] = name
             else:
-                self[date(year, JUN, 26)] = name
+                collect_holiday(date(year, JUN, 26), name)
 
         # Independence Day
         if year <= 2005:
-            self[date(year, OCT, 18)] = "Independence Day"
+            collect_holiday(date(year, OCT, 18), "Independence Day")
 
         # Victory Day
         if year >= 2021:
-            self[date(year, NOV, 8)] = "Victory Day"
+            collect_holiday(date(year, NOV, 8), "Victory Day")
 
         # Flag Day
         if year >= 2010:
-            self[date(year, NOV, 9)] = "Flag Day"
+            collect_holiday(date(year, NOV, 9), "Flag Day")
 
         # International Solidarity Day of Azerbaijanis
         if year >= 1993:
             name = "International Solidarity Day of Azerbaijanis"
-            self[date(year, DEC, 31)] = name
-            if self.observed and year >= 2006:
-                dt = date(year - 1, DEC, 31)
-                if self._is_weekend(dt):
-                    _add_observed(dt, name)
+            collect_holiday(date(year, DEC, 31), name)
+            collect_holiday(date(year - 1, DEC, 31), name)
 
         ramazan_dates_obs = {
             2011: ((AUG, 30),),
@@ -147,45 +143,63 @@ def _add_holiday(hol_date: date, hol_name: str) -> None:
                 for yr in (year - 1, year):
                     if yr in dates_obs:
                         for date_obs in dates_obs[yr]:
-                            _add_holiday(date(yr, *date_obs), name)
-                            _add_holiday(
+                            collect_holiday(date(yr, *date_obs), name)
+                            collect_holiday(
                                 date(yr, *date_obs) + td(days=+1), name
                             )
                     else:
                         for dt in _islamic_to_gre(yr, hmonth, hday):
-                            _add_holiday(dt, f"{name}* (*estimated)")
-                            _add_holiday(
+                            collect_holiday(dt, f"{name}* (*estimated)")
+                            collect_holiday(
                                 dt + td(days=+1),
                                 f"{name}* (*estimated)",
                             )
 
-        """
-        [2]:
-        Article 105 of the Labor Code of the Republic of Azerbaijan states:
-        5. If interweekly rest days and holidays that are not considered
-        working days overlap, that rest day is immediately transferred to
-        the next working day.
-        6. If the holidays of Qurban and Ramadan coincide with another holiday
-        that is not considered a working day, the next working day is
-         considered a rest day. *(machine translated)*
-        """
+        # Article 105 of the Labor Code of the Republic of Azerbaijan states:
+        # 5. If interweekly rest days and holidays that are not considered
+        # working days overlap, that rest day is immediately transferred to
+        # the next working day.
         if self.observed and year >= 2006:
-            for k, v in list(self.items()):
-                if (
-                    k.year == year
-                    and self._is_weekend(k)
-                    and k
-                    not in (
-                        date(year, JAN, 20),
-                        date(year, SEP, 27),
+            hol_dates = list(holiday_date_names_mapping.keys())
+            hol_dates.append(date(year, JAN, 20))
+            hol_dates.append(date(year, SEP, 27))
+
+            for hol_date, hol_names in sorted(
+                holiday_date_names_mapping.items()
+            ):
+                if self._is_weekend(hol_date):
+                    next_workday = hol_date + td(
+                        days=+2 if self._is_saturday(hol_date) else +1
                     )
-                ):
-                    _add_observed(k, v)
-                hol_names = self.get_list(k)
-                if len(hol_names) > 1 and " (Observed)" not in v:
-                    for name in hol_names:
-                        if name in {hol[0] for hol in religious_holidays}:
-                            _add_observed(k, name)
+                    while next_workday in hol_dates or self._is_weekend(
+                        next_workday
+                    ):
+                        next_workday += td(days=+1)
+                    for hol_name in hol_names:
+                        collect_holiday(next_workday, f"{hol_name} (Observed)")
+                    hol_dates.append(next_workday)
+
+                # 6. If the holidays of Qurban and Ramadan coincide with
+                # another holiday that is not considered a working day,
+                # the next working day is considered a rest day.
+                elif len(hol_names) > 1:
+                    for hol_name in hol_names:
+                        if "Bayrami" in hol_name:
+                            next_workday = hol_date + td(days=+1)
+                            while (
+                                next_workday in hol_dates
+                                or self._is_weekend(next_workday)
+                            ):
+                                next_workday += td(days=+1)
+                            collect_holiday(
+                                next_workday, f"{hol_name} (Observed)"
+                            )
+                            hol_dates.append(next_workday)
+
+        for hol_date, hol_names in holiday_date_names_mapping.items():
+            if hol_date.year == year:
+                for hol_name in hol_names:
+                    self[hol_date] = hol_name
 
 
 class AZ(Azerbaijan):
diff --git a/holidays/countries/bahrain.py b/holidays/countries/bahrain.py
index 2594ab939..abfde5ca7 100644
--- a/holidays/countries/bahrain.py
+++ b/holidays/countries/bahrain.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import FRI, SAT, JAN, MAY, JUL, AUG, OCT, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Bahrain(HolidayBase):
diff --git a/holidays/countries/bosnia_and_herzegovina.py b/holidays/countries/bosnia_and_herzegovina.py
index c0dc8cff7..94262f66c 100644
--- a/holidays/countries/bosnia_and_herzegovina.py
+++ b/holidays/countries/bosnia_and_herzegovina.py
@@ -15,9 +15,9 @@
 
 from dateutil.easter import EASTER_ORTHODOX, easter
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, MAY, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class BosniaAndHerzegovina(HolidayBase):
diff --git a/holidays/countries/botswana.py b/holidays/countries/botswana.py
index 8e89ee570..cf3aba4a9 100644
--- a/holidays/countries/botswana.py
+++ b/holidays/countries/botswana.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAY, JUL, SEP, DEC
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, MAY, JUL, SEP, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -74,7 +73,8 @@ def _add_with_observed(
         _add_with_observed(date(year, JUL, 1), "Sir Seretse Khama Day")
 
         # 3rd Monday of July = "President's Day"
-        dt = date(year, JUL, 1) + rd(weekday=MO(+3))
+        dt = _get_nth_weekday_of_month(3, MON, JUL, year)
+
         self[dt] = "President's Day"
         self[dt + td(days=+1)] = "President's Day Holiday"
 
diff --git a/holidays/countries/brazil.py b/holidays/countries/brazil.py
index ed527090d..23051de7e 100644
--- a/holidays/countries/brazil.py
+++ b/holidays/countries/brazil.py
@@ -13,11 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import SU
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _get_nth_weekday_from
 from holidays.constants import JAN, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT
-from holidays.constants import NOV, DEC
+from holidays.constants import NOV, DEC, SUN
 from holidays.holiday_base import HolidayBase
 
 
@@ -190,7 +189,7 @@ def _populate(self, year):
         if self.subdiv == "SC":
             dt = date(year, AUG, 11)
             if year >= 2018 and not self._is_weekend(dt):
-                dt += rd(weekday=SU)
+                dt = _get_nth_weekday_from(1, SUN, dt)
             self[dt] = "Criação da capitania, separando-se de SP"
 
         if self.subdiv == "SP":
diff --git a/holidays/countries/burundi.py b/holidays/countries/burundi.py
index 291144661..86a0d69a7 100644
--- a/holidays/countries/burundi.py
+++ b/holidays/countries/burundi.py
@@ -14,9 +14,9 @@
 
 from dateutil.easter import easter
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, FEB, APR, MAY, JUN, JUL, AUG, OCT, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Burundi(HolidayBase):
diff --git a/holidays/countries/canada.py b/holidays/countries/canada.py
index e9ef2e7a0..bf30b5900 100644
--- a/holidays/countries/canada.py
+++ b/holidays/countries/canada.py
@@ -13,11 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO, SU
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
-from holidays.constants import OCT, NOV, DEC
+from holidays.constants import OCT, NOV, DEC, SUN, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -47,10 +46,8 @@ def __init__(self, **kwargs):
         HolidayBase.__init__(self, **kwargs)
 
     def _get_nearest_monday(self, dt: date) -> date:
-        return (
-            dt + rd(weekday=MO(-1))
-            if not self._is_friday(dt) and not self._is_weekend(dt)
-            else dt + rd(weekday=MO)
+        return _get_nth_weekday_from(
+            1 if self._is_friday(dt) or self._is_weekend(dt) else -1, MON, dt
         )
 
     def _populate(self, year):
@@ -63,7 +60,7 @@ def _populate(self, year):
         name = self.tr("New Year's Day")
         self[date(year, JAN, 1)] = name
         if self.observed and self._is_weekend(year, JAN, 1):
-            self[date(year, JAN, 1) + rd(weekday=MO)] = (
+            self[_get_nth_weekday_of_month(1, MON, JAN, year)] = (
                 self.tr("%s (Observed)") % name
             )
 
@@ -75,34 +72,34 @@ def _populate(self, year):
             or (self.subdiv == "ON" and year >= 2008)
             or (self.subdiv == "NB" and year >= 2018)
         ):
-            self[date(year, FEB, 1) + rd(weekday=MO(+3))] = self.tr(
+            self[_get_nth_weekday_of_month(3, MON, FEB, year)] = self.tr(
                 "Family Day"
             )
         elif self.subdiv == "BC":
             if 2013 <= year <= 2018:
-                self[date(year, FEB, 1) + rd(weekday=MO(+2))] = self.tr(
+                self[_get_nth_weekday_of_month(2, MON, FEB, year)] = self.tr(
                     "Family Day"
                 )
             elif year > 2018:
-                self[date(year, FEB, 1) + rd(weekday=MO(+3))] = self.tr(
+                self[_get_nth_weekday_of_month(3, MON, FEB, year)] = self.tr(
                     "Family Day"
                 )
         elif self.subdiv == "MB" and year >= 2008:
-            self[date(year, FEB, 1) + rd(weekday=MO(+3))] = self.tr(
+            self[_get_nth_weekday_of_month(3, MON, FEB, year)] = self.tr(
                 "Louis Riel Day"
             )
         elif self.subdiv == "PE" and year >= 2010:
-            self[date(year, FEB, 1) + rd(weekday=MO(+3))] = self.tr(
+            self[_get_nth_weekday_of_month(3, MON, FEB, year)] = self.tr(
                 "Islander Day"
             )
         elif self.subdiv == "PE" and year == 2009:
-            self[date(year, FEB, 1) + rd(weekday=MO(+2))] = self.tr(
+            self[_get_nth_weekday_of_month(2, MON, FEB, year)] = self.tr(
                 "Islander Day"
             )
         # http://novascotia.ca/lae/employmentrights/NovaScotiaHeritageDay.asp
         elif self.subdiv == "NS" and year >= 2015:
             # Heritage Day.
-            self[date(year, FEB, 1) + rd(weekday=MO(+3))] = self.tr(
+            self[_get_nth_weekday_of_month(3, MON, FEB, year)] = self.tr(
                 "Heritage Day"
             )
         elif self.subdiv == "YT" and year >= 1974:
@@ -114,12 +111,7 @@ def _populate(self, year):
             # http://heritageyukon.ca/programs/heritage-day
             # https://en.wikipedia.org/wiki/Family_Day_(Canada)#Yukon_Heritage_Day
             # Friday before the last Sunday in February
-            dt = (
-                date(year, MAR, 1)
-                + td(days=-1)
-                + rd(weekday=SU(-1))
-                + td(days=-2)
-            )
+            dt = _get_nth_weekday_of_month(-1, SUN, FEB, year) + td(days=-2)
             # Heritage Day.
             self[dt] = self.tr("Heritage Day")
 
@@ -149,7 +141,7 @@ def _populate(self, year):
 
         # Victoria Day / National Patriots' Day (QC)
         if year >= 1953:
-            dt = date(year, MAY, 24) + rd(weekday=MO(-1))
+            dt = _get_nth_weekday_from(-1, MON, date(year, MAY, 24))
             if self.subdiv not in {"NB", "NS", "PE", "NL", "QC"}:
                 self[dt] = self.tr("Victoria Day")
             elif self.subdiv == "QC":
@@ -173,7 +165,7 @@ def _populate(self, year):
             dt = self._get_nearest_monday(date(year, JUN, 24))
             self[dt] = self.tr("Discovery Day")
         elif self.subdiv == "YT" and year >= 1912:
-            self[date(year, AUG, 1) + rd(weekday=MO(+3))] = self.tr(
+            self[_get_nth_weekday_of_month(3, MON, AUG, year)] = self.tr(
                 "Discovery Day"
             )
 
@@ -189,7 +181,9 @@ def _populate(self, year):
         dt = date(year, JUL, 1)
         self[dt] = name
         if year >= 1879 and self.observed and self._is_weekend(dt):
-            self[dt + rd(weekday=MO)] = self.tr("%s (Observed)") % name
+            self[_get_nth_weekday_from(1, MON, dt)] = (
+                self.tr("%s (Observed)") % name
+            )
 
         # Nunavut Day
         if self.subdiv == "NU":
@@ -204,33 +198,37 @@ def _populate(self, year):
 
         # Civic Holiday
         if year >= 1900 and self.subdiv in {"MB", "NT", "ON"}:
-            self[date(year, AUG, 1) + rd(weekday=MO)] = self.tr(
+            self[_get_nth_weekday_of_month(1, MON, AUG, year)] = self.tr(
                 "Civic Holiday"
             )
         # https://en.wikipedia.org/wiki/Civic_Holiday#Alberta
         elif year >= 1974 and self.subdiv == "AB":
             # Heritage Day.
-            self[date(year, AUG, 1) + rd(weekday=MO)] = self.tr("Heritage Day")
+            self[_get_nth_weekday_of_month(1, MON, AUG, year)] = self.tr(
+                "Heritage Day"
+            )
         # https://en.wikipedia.org/wiki/Civic_Holiday
         elif year >= 1974 and self.subdiv == "BC":
             # British Columbia Day.
-            self[date(year, AUG, 1) + rd(weekday=MO)] = self.tr(
+            self[_get_nth_weekday_of_month(1, MON, AUG, year)] = self.tr(
                 "British Columbia Day"
             )
         # https://en.wikipedia.org/wiki/Civic_Holiday
         elif year >= 1900 and self.subdiv == "NB":
-            self[date(year, AUG, 1) + rd(weekday=MO)] = self.tr(
+            self[_get_nth_weekday_of_month(1, MON, AUG, year)] = self.tr(
                 "New Brunswick Day"
             )
         # https://en.wikipedia.org/wiki/Civic_Holiday
         elif year >= 1900 and self.subdiv == "SK":
-            self[date(year, AUG, 1) + rd(weekday=MO)] = self.tr(
+            self[_get_nth_weekday_of_month(1, MON, AUG, year)] = self.tr(
                 "Saskatchewan Day"
             )
 
         # Labour Day
         if year >= 1894:
-            self[date(year, SEP, 1) + rd(weekday=MO)] = self.tr("Labour Day")
+            self[_get_nth_weekday_of_month(1, MON, SEP, year)] = self.tr(
+                "Labour Day"
+            )
 
         # Funeral of Queen Elizabeth II
         # https://www.narcity.com/provinces-territories-will-have-a-day-off-monday-mourn-queen
@@ -263,7 +261,7 @@ def _populate(self, year):
             if year == 1935:
                 self[date(1935, OCT, 25)] = self.tr("Thanksgiving")
             else:
-                self[date(year, OCT, 1) + rd(weekday=MO(+2))] = self.tr(
+                self[_get_nth_weekday_of_month(2, MON, OCT, year)] = self.tr(
                     "Thanksgiving"
                 )
 
@@ -277,7 +275,9 @@ def _populate(self, year):
                 and self._is_sunday(dt)
                 and self.subdiv in {"NS", "NL", "NT", "PE", "SK"}
             ):
-                self[dt + rd(weekday=MO)] = self.tr("%s (Observed)") % name
+                self[_get_nth_weekday_from(1, MON, dt)] = (
+                    self.tr("%s (Observed)") % name
+                )
 
         # Christmas Day,
         name = self.tr("Christmas Day")
diff --git a/holidays/countries/chile.py b/holidays/countries/chile.py
index 7779ed725..6ca1efcc9 100644
--- a/holidays/countries/chile.py
+++ b/holidays/countries/chile.py
@@ -9,19 +9,24 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-from datetime import date, datetime
+from datetime import date, datetime, timezone
 from datetime import timedelta as td
+from gettext import gettext as tr
 
-from dateutil import tz
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 from pymeeus.Epoch import Epoch
 from pymeeus.Sun import Sun
 
-from holidays.constants import JAN, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
+from holidays.constants import JAN, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC, MON
 from holidays.holiday_base import HolidayBase
 
+# use standard library for timezone
+try:
+    from zoneinfo import ZoneInfo
+except ImportError:  # pragma: no cover
+    from backports.zoneinfo import ZoneInfo  # type: ignore[no-redef]
+
 
 class Chile(HolidayBase):
     """
@@ -32,8 +37,9 @@ class Chile(HolidayBase):
 
     country = "CL"
     special_holidays = {
-        2022: ((SEP, 16, "Feriado nacional [National Holiday]"),),
+        2022: ((SEP, 16, tr("Feriado nacional")),),
     }
+    default_language = "es"
     # ISO 3166-2 codes for the principal subdivisions, called regions
     subdivisions = [
         "AI",
@@ -55,6 +61,15 @@ class Chile(HolidayBase):
     ]
 
     def _populate(self, year):
+        def _get_movable(hol_date: date) -> date:
+            if year >= 2000:
+                # floating Monday holiday (Law 19.668)
+                if self._is_friday(hol_date):
+                    hol_date = _get_nth_weekday_from(1, MON, hol_date)
+                elif not self._is_weekend(hol_date):
+                    hol_date = _get_nth_weekday_from(-1, MON, hol_date)
+            return hol_date
+
         # Law 2.977 established official holidays for Chile
         # in its current form
         if year <= 1914:
@@ -63,47 +78,35 @@ def _populate(self, year):
         super()._populate(year)
 
         # New Year's Day (Law 2.977)
-        self[date(year, JAN, 1)] = "Año Nuevo [New Year's Day]"
+        self[date(year, JAN, 1)] = self.tr("Año Nuevo")
         # Day after, if it's a Sunday (Law 20.983)
         if year >= 2017 and self._is_sunday(date(year, JAN, 1)):
-            self[date(year, JAN, 2)] = "Fiestas Patrias [Holiday]"
+            self[date(year, JAN, 2)] = self.tr("Feriado nacional")
 
         # Holy Week (Law 2.977)
         easter_date = easter(year)
-        self[
-            easter_date + td(days=-2)
-        ] = "Semana Santa (Viernes Santo) [Good Friday)]"
-        self[
-            easter_date + td(days=-1)
-        ] = "Semana Santa (Sábado Santo) [Good Saturday)]"
+        self[easter_date + td(days=-2)] = self.tr("Viernes Santo")
+        self[easter_date + td(days=-1)] = self.tr("Sábado Santo")
 
         # Ascension
         if year <= 1967:
-            self[
-                easter_date + td(days=+39)
-            ] = "Ascensión del Señor [Ascension of Jesus]"
+            self[easter_date + td(days=+39)] = self.tr("Ascensión del Señor")
 
         # Corpus Christi
         if year <= 1967 or 1987 <= year <= 2006:
             # Law 19.668
-            if year <= 1999:
-                dt = easter_date + td(days=+60)
-            else:
-                dt = easter_date + td(days=+57)
-            self[dt] = "Corpus Christi [Corpus Christi]"
+            delta = +60 if year <= 1999 else +57
+            self[easter_date + td(days=delta)] = self.tr("Corpus Christi")
 
         # Labour Day (Law 2.200, renamed with Law 18.018)
         if year >= 1932:
-            self[date(year, MAY, 1)] = "Día Nacional del Trabajo [Labour Day]"
+            self[date(year, MAY, 1)] = self.tr("Día Nacional del Trabajo")
 
         # Naval Glories Day (Law 2.977)
-        self[date(year, MAY, 21)] = "Día de las Glorias Navales [Navy Day]"
+        self[date(year, MAY, 21)] = self.tr("Día de las Glorias Navales")
 
         # National Day of Indigenous Peoples
-        name = (
-            "Día Nacional de los Pueblos Indígenas "
-            "[National Day of Indigenous Peoples]"
-        )
+        name = self.tr("Día Nacional de los Pueblos Indígenas")
         if year == 2021:
             self[date(year, JUN, 21)] = name
         elif year >= 2022:
@@ -112,93 +115,65 @@ def _populate(self, year):
             # to match Chile's timezone
             # https://www.feriadoschilenos.cl/#DiaNacionalDeLosPueblosIndigenasII
             equinox = map(int, Epoch(epoch).get_full_date())
-            adjusted_date = datetime(*equinox, tzinfo=tz.UTC).astimezone(
-                tz.gettz("America/Santiago")
+            adjusted_date = datetime(*equinox, tzinfo=timezone.utc).astimezone(
+                ZoneInfo("America/Santiago")
             )
             self[date(year, JUN, adjusted_date.day)] = name
 
         # Saint Peter and Saint Paul (Law 16.840, Law 18.432)
         if year <= 1967 or year >= 1986:
-            dt = date(year, JUN, 29)
-            if year >= 2000:
-                # floating Monday holiday (Law 19.668)
-                if not self._is_friday(dt) and not self._is_weekend(dt):
-                    dt += rd(weekday=MO(-1))
-                elif self._is_friday(dt):
-                    dt += rd(weekday=MO)
-            self[dt] = "San Pedro y San Pablo [Saint Peter and Saint Paul]"
+            self[_get_movable(date(year, JUN, 29))] = self.tr(
+                "San Pedro y San Pablo"
+            )
 
         # Day of Virgin of Carmen (Law 20.148)
         if year >= 2007:
-            self[
-                date(year, JUL, 16)
-            ] = "Virgen del Carmen [Our Lady of Mount Carmel]"
+            self[date(year, JUL, 16)] = self.tr("Virgen del Carmen")
 
         # Day of Assumption of the Virgin (Law 2.977)
-        self[
-            date(year, AUG, 15)
-        ] = "Asunción de la Virgen [Assumption of Mary]"
+        self[date(year, AUG, 15)] = self.tr("Asunción de la Virgen")
 
         # Day of National Liberation (Law 18.026)
         if 1981 <= year <= 1998:
-            self[
-                date(year, SEP, 11)
-            ] = "Día de la Liberación Nacional [Day of National Liberation]"
+            self[date(year, SEP, 11)] = self.tr(
+                "Día de la Liberación Nacional"
+            )
         # Day of National Unity (Law 19.588, Law 19.793)
         elif 1999 <= year <= 2001:
-            self[
-                date(year, SEP, 1) + rd(weekday=MO)
-            ] = "Día de la Unidad Nacional [Day of National Unity]"
+            self[_get_nth_weekday_of_month(1, MON, SEP, year)] = self.tr(
+                "Día de la Unidad Nacional"
+            )
 
         # National Holiday Friday preceding Independence Day (Law 20.983)
         # Monday, September 17, 2007, is declared a holiday.
         if year >= 2017 and self._is_saturday(date(year, SEP, 18)):
-            self[date(year, SEP, 17)] = "Fiestas Patrias [Holiday]"
+            self[date(year, SEP, 17)] = self.tr("Fiestas Patrias")
 
         # National Holiday Monday preceding Independence Day (Law 20.215)
         if year >= 2007 and self._is_tuesday(date(year, SEP, 18)):
-            self[date(year, SEP, 17)] = "Fiestas Patrias [Holiday]"
+            self[date(year, SEP, 17)] = self.tr("Fiestas Patrias")
 
         # Independence Day (Law 2.977)
-        self[
-            date(year, SEP, 18)
-        ] = "Día de la Independencia [Independence Day]"
+        self[date(year, SEP, 18)] = self.tr("Día de la Independencia")
 
         # Day of Glories of the Army of Chile (Law 2.977)
-        self[
-            date(year, SEP, 19)
-        ] = "Día de las Glorias del Ejército [Army Day]"
+        self[date(year, SEP, 19)] = self.tr("Día de las Glorias del Ejército")
 
         # National Holiday Friday following Army Day (Law 20.215)
         if year >= 2008 and self._is_thursday(date(year, SEP, 19)):
-            self[date(year, SEP, 20)] = "Fiestas Patrias [Holiday]"
+            self[date(year, SEP, 20)] = self.tr("Fiestas Patrias")
 
         # Decree-law 636, Law 8.223
         if 1932 <= year <= 1944:
-            self[date(year, SEP, 20)] = "Fiestas Patrias [Holiday]"
+            self[date(year, SEP, 20)] = self.tr("Fiestas Patrias")
 
         # Columbus day (Law 3.810)
         if year >= 1922 and year != 1973:
-            dt = date(year, OCT, 12)
-            name = "Día de la Raza [Columbus day]"
-            if year >= 2000:
-                # floating Monday holiday (Law 19.668)
-                if not self._is_friday(dt) and not self._is_weekend(dt):
-                    dt += rd(weekday=MO(-1))
-                elif self._is_friday(dt):
-                    dt += rd(weekday=MO)
-                if year <= 2019:
-                    # Day of the Meeting of Two Worlds (Law 3.810)
-                    name = (
-                        "Día del Respeto a la Diversidad "
-                        "[Day of the Meeting of Two Worlds]"
-                    )
-                else:
-                    name = (
-                        "Día del Descubrimiento de dos Mundos "
-                        "[Discovery of Two Worlds' Day]"
-                    )
-            self[dt] = name
+            self[_get_movable(date(year, OCT, 12))] = (
+                self.tr("Día del Encuentro de dos Mundos")
+                if year >= 2000
+                else self.tr("Día de la Raza")
+            )
 
         # National Day of the Evangelical and Protestant Churches (Law 20.299)
         if year >= 2008:
@@ -210,40 +185,35 @@ def _populate(self, year):
                 dt += td(days=+2)
             elif self._is_tuesday(dt):
                 dt += td(days=-4)
-            self[dt] = (
+            self[dt] = self.tr(
                 "Día Nacional de las Iglesias Evangélicas y Protestantes"
-                " [Reformation Day]"
             )
 
         # All Saints Day (Law 2.977)
-        self[date(year, NOV, 1)] = "Día de Todos los Santos [All Saints Day]"
+        self[date(year, NOV, 1)] = self.tr("Día de Todos los Santos")
 
         # Immaculate Conception (Law 2.977)
-        self[
-            date(year, DEC, 8)
-        ] = "La Inmaculada Concepción [Immaculate Conception]"
+        self[date(year, DEC, 8)] = self.tr("La Inmaculada Concepción")
 
         if 1944 <= year <= 1988:
-            self[date(year, DEC, 24)] = "Víspera de Navidad [Christmas Eve]"
+            self[date(year, DEC, 24)] = self.tr("Víspera de Navidad")
 
         # Christmas (Law 2.977)
-        self[date(year, DEC, 25)] = "Navidad [Christmas]"
+        self[date(year, DEC, 25)] = self.tr("Navidad")
 
         # región de Arica y Parinacota
         if self.subdiv == "AP" and year >= 2013:
             # Law 20.663
-            self[date(year, JUN, 7)] = (
+            self[date(year, JUN, 7)] = self.tr(
                 "Asalto y Toma del Morro de Arica"
-                " [Assault and Capture of Cape Arica]"
             )
 
         # región de Ñuble
         if self.subdiv == "NB" and year >= 2014:
             # Law 20.678
-            self[date(year, AUG, 20)] = (
+            self[date(year, AUG, 20)] = self.tr(
                 "Nacimiento del Prócer de la Independencia"
                 " (Chillán y Chillán Viejo)"
-                " [Nativity of Bernardo O'Higgins]"
             )
 
 
diff --git a/holidays/countries/china.py b/holidays/countries/china.py
index 422532061..e5d99b19f 100644
--- a/holidays/countries/china.py
+++ b/holidays/countries/china.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _ChineseLuniSolar
 from holidays.constants import JAN, APR, MAY, OCT
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _ChineseLuniSolar
 
 
 class China(HolidayBase):
diff --git a/holidays/countries/colombia.py b/holidays/countries/colombia.py
index 78a01925f..5e2f7047d 100644
--- a/holidays/countries/colombia.py
+++ b/holidays/countries/colombia.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAR, MAY, JUN, JUL, AUG, OCT, NOV, DEC
+from holidays.calendars import _get_nth_weekday_from
+from holidays.constants import JAN, MAR, MAY, JUN, JUL, AUG, OCT, NOV, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -30,8 +29,9 @@ class Colombia(HolidayBase):
     """
 
     country = "CO"
+    default_language = "es"
 
-    def _add_with_bridge(self, dt, name):
+    def _add_with_bridge(self, dt: date, name: str) -> None:
         """
         On the 6th of December 1983, the government of Colombia declared which
         holidays are to take effect, and also clarified that a subset of them
@@ -47,133 +47,107 @@ def _add_with_bridge(self, dt, name):
         1984: https://bit.ly/3B7ogt8
         """
 
-        if self.observed and not self._is_monday(dt) and dt.year > 1983:
-            self[dt + rd(weekday=MO)] = name + " (Observed)"
+        if self.observed and not self._is_monday(dt) and dt.year >= 1984:
+            self[_get_nth_weekday_from(1, MON, dt)] = (
+                self.tr("%s (Observado)") % name
+            )
         else:
             self[dt] = name
 
     def _populate(self, year):
         super()._populate(year)
 
-        self._add_fixed_date_holidays(year)
-        self._add_flexible_date_holidays(year)
-        self._add_easter_based_holidays(year)
-
-    def _add_fixed_date_holidays(self, year):
-        """
-        These holidays are always on the same date no matter what day of the
-        week they fall on.
-        """
-
         # New Year's Day
-        self[date(year, JAN, 1)] = "Año Nuevo [New Year's Day]"
-
-        # Labor Day
-        self[date(year, MAY, 1)] = "Día del Trabajo [Labour Day]"
-
-        # Independence Day
-        self[
-            date(year, JUL, 20)
-        ] = "Día de la Independencia [Independence Day]"
-
-        # Battle of Boyaca
-        self[date(year, AUG, 7)] = "Batalla de Boyacá [Battle of Boyacá]"
-
-        if year > 1950:
-            # Immaculate Conception
-            self[
-                date(year, DEC, 8)
-            ] = "La Inmaculada Concepción [Immaculate Conception]"
-
-        # Christmas
-        self[date(year, DEC, 25)] = "Navidad [Christmas]"
+        self[date(year, JAN, 1)] = self.tr("Año Nuevo")
 
-    def _add_flexible_date_holidays(self, year):
-        """
-        These holidays fall on the next Monday if they are not already on
-        Monday.
-        """
-
-        if year > 1950:
+        if year >= 1951:
             # Epiphany
             self._add_with_bridge(
                 date(year, JAN, 6),
-                "Día de los Reyes Magos [Epiphany]",
+                self.tr("Día de los Reyes Magos"),
             )
 
             # Saint Joseph's Day
             self._add_with_bridge(
                 date(year, MAR, 19),
-                "Día de San José [Saint Joseph's Day]",
+                self.tr("Día de San José"),
             )
 
+        # Labor Day
+        self[date(year, MAY, 1)] = self.tr("Día del Trabajo")
+
+        if year >= 1951:
             # Saint Peter and Saint Paul's Day
             self._add_with_bridge(
                 date(year, JUN, 29),
-                "San Pedro y San Pablo [Saint Peter and Saint Paul]",
+                self.tr("San Pedro y San Pablo"),
             )
 
+        # Independence Day
+        self[date(year, JUL, 20)] = self.tr("Día de la Independencia")
+
+        # Battle of Boyaca
+        self[date(year, AUG, 7)] = self.tr("Batalla de Boyacá")
+
+        if year >= 1951:
             # Assumption of Mary
             self._add_with_bridge(
                 date(year, AUG, 15),
-                "La Asunción [Assumption of Mary]",
+                self.tr("La Asunción"),
             )
 
         # Columbus Day
         self._add_with_bridge(
             date(year, OCT, 12),
-            "Día de la Raza [Columbus Day]",
+            self.tr("Día de la Raza"),
         )
 
-        if year > 1950:
+        if year >= 1951:
             # All Saints’ Day
             self._add_with_bridge(
                 date(year, NOV, 1),
-                "Día de Todos los Santos [All Saint's Day]",
+                self.tr("Día de Todos los Santos"),
             )
 
         # Independence of Cartagena
         self._add_with_bridge(
             date(year, NOV, 11),
-            "Independencia de Cartagena [Independence of Cartagena]",
+            self.tr("Independencia de Cartagena"),
         )
 
-    def _add_easter_based_holidays(self, year):
-        """
-        These holidays change each year based on when easter is.
-        """
+        if year >= 1951:
+            # Immaculate Conception
+            self[date(year, DEC, 8)] = self.tr("La Inmaculada Concepción")
+
+        # Christmas
+        self[date(year, DEC, 25)] = self.tr("Navidad")
 
-        _easter = easter(year)
-        self._add_fixed_easter_based_holidays(_easter)
-        self._add_flexible_easter_based_holidays(_easter)
+        easter_date = easter(year)
 
-    def _add_fixed_easter_based_holidays(self, _easter):
-        if _easter.year > 1950:
+        if year >= 1951:
             # Maundy Thursday
-            self[_easter + td(days=-3)] = "Jueves Santo [Maundy Thursday]"
+            self[easter_date + td(days=-3)] = self.tr("Jueves Santo")
 
             # Good Friday
-            self[_easter + td(days=-2)] = "Viernes Santo [Good Friday]"
+            self[easter_date + td(days=-2)] = self.tr("Viernes Santo")
 
-    def _add_flexible_easter_based_holidays(self, _easter):
-        if _easter.year > 1950:
             # Ascension of Jesus
             self._add_with_bridge(
-                _easter + td(days=+39),
-                "Ascensión del señor [Ascension of Jesus]",
+                easter_date + td(days=+39),
+                self.tr("Ascensión del señor"),
             )
 
             # Corpus Christi
             self._add_with_bridge(
-                _easter + td(days=+60),
-                "Corpus Christi [Corpus Christi]",
+                easter_date + td(days=+60),
+                self.tr("Corpus Christi"),
             )
 
-        if _easter.year > 1983:
+        if year >= 1984:
             # Sacred Heart
             self._add_with_bridge(
-                _easter + td(days=+68),
-                "Sagrado Corazón [Sacred Heart]",
+                easter_date + td(days=+68),
+                self.tr("Sagrado Corazón"),
             )
 
 
diff --git a/holidays/countries/djibouti.py b/holidays/countries/djibouti.py
index e0e84cf6f..f3cb0b9b6 100644
--- a/holidays/countries/djibouti.py
+++ b/holidays/countries/djibouti.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAY, JUN, FRI, SAT
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 # Since Djibouti share most of it's holidays with other muslim countries,
 # this class is just a copy of Egypt's.
diff --git a/holidays/countries/dominican_republic.py b/holidays/countries/dominican_republic.py
index 1e15b3abd..3443441d2 100644
--- a/holidays/countries/dominican_republic.py
+++ b/holidays/countries/dominican_republic.py
@@ -13,11 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _get_nth_weekday_from
 from holidays.constants import JAN, FEB, MAY, JUN, AUG, SEP, NOV, DEC, TUE
-from holidays.constants import WED, THU, FRI, SUN
+from holidays.constants import MON, WED, THU, FRI, SUN
 from holidays.holiday_base import HolidayBase
 
 
@@ -34,9 +33,9 @@ def __change_day_by_law(holiday, latest_days=(THU, FRI)):
         # Law No. 139-97 - Holidays Dominican Republic - Jun 27, 1997
         if holiday >= date(1997, JUN, 27):
             if holiday.weekday() in {TUE, WED}:
-                holiday += rd(weekday=MO(-1))
+                holiday = _get_nth_weekday_from(-1, MON, holiday)
             elif holiday.weekday() in latest_days:
-                holiday += rd(weekday=MO(+1))
+                holiday = _get_nth_weekday_from(1, MON, holiday)
         return holiday
 
     def _populate(self, year):
diff --git a/holidays/countries/egypt.py b/holidays/countries/egypt.py
index 48ec830a2..bfec57436 100644
--- a/holidays/countries/egypt.py
+++ b/holidays/countries/egypt.py
@@ -14,9 +14,9 @@
 
 from dateutil.easter import EASTER_ORTHODOX, easter
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, APR, MAY, JUN, JUL, OCT
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Egypt(HolidayBase):
diff --git a/holidays/countries/ethiopia.py b/holidays/countries/ethiopia.py
index eda6521c9..3ae354dda 100644
--- a/holidays/countries/ethiopia.py
+++ b/holidays/countries/ethiopia.py
@@ -14,9 +14,9 @@
 
 from dateutil.easter import easter, EASTER_ORTHODOX
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, MAY, SEP
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 # Ethiopian holidays are estimated: it is common for the day to be pushed
 # if falls in a weekend, although not a rule that can be implemented.
diff --git a/holidays/countries/finland.py b/holidays/countries/finland.py
index 21018ef5c..3272aa114 100644
--- a/holidays/countries/finland.py
+++ b/holidays/countries/finland.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import FR, SA
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAY, JUN, OCT, DEC
+from holidays.calendars import _get_nth_weekday_from
+from holidays.constants import JAN, MAY, JUN, OCT, DEC, FRI, SAT
 from holidays.holiday_base import HolidayBase
 
 
@@ -40,15 +39,21 @@ def _populate(self, year):
         self[date(year, MAY, 1)] = "Vappu"
         self[easter_date + td(days=+39)] = "Helatorstai"
         self[easter_date + td(days=+49)] = "Helluntaipäivä"
-        self[date(year, JUN, 20) + rd(weekday=SA)] = "Juhannuspäivä"
-        self[date(year, OCT, 31) + rd(weekday=SA)] = "Pyhäinpäivä"
+        self[
+            _get_nth_weekday_from(1, SAT, date(year, JUN, 20))
+        ] = "Juhannuspäivä"
+        self[
+            _get_nth_weekday_from(1, SAT, date(year, OCT, 31))
+        ] = "Pyhäinpäivä"
         self[date(year, DEC, 6)] = "Itsenäisyyspäivä"
         self[date(year, DEC, 25)] = "Joulupäivä"
         self[date(year, DEC, 26)] = "Tapaninpäivä"
 
         # Juhannusaatto (Midsummer Eve) and Jouluaatto (Christmas Eve) are not
         # official holidays, but are de facto.
-        self[date(year, JUN, 19) + rd(weekday=FR)] = "Juhannusaatto"
+        self[
+            _get_nth_weekday_from(1, FRI, date(year, JUN, 19))
+        ] = "Juhannusaatto"
         self[date(year, DEC, 24)] = "Jouluaatto"
 
 
diff --git a/holidays/countries/germany.py b/holidays/countries/germany.py
index 859d6c7a6..0274842c5 100644
--- a/holidays/countries/germany.py
+++ b/holidays/countries/germany.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import WE
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAR, MAY, AUG, SEP, OCT, NOV, DEC
+from holidays.calendars import _get_nth_weekday_from
+from holidays.constants import JAN, MAR, MAY, AUG, SEP, OCT, NOV, DEC, WED
 from holidays.holiday_base import HolidayBase
 
 
@@ -138,7 +137,9 @@ def _populate(self, year):
 
         if year <= 1994 or self.subdiv == "SN":
             # last wednesday before year-11-23
-            self[date(year, NOV, 22) + rd(weekday=WE(-1))] = "Buß- und Bettag"
+            self[
+                _get_nth_weekday_from(-1, WED, date(year, NOV, 22))
+            ] = "Buß- und Bettag"
 
         if year >= 2019:
             if self.subdiv == "TH":
diff --git a/holidays/countries/greece.py b/holidays/countries/greece.py
index c7a3b4ff8..fd9e86611 100644
--- a/holidays/countries/greece.py
+++ b/holidays/countries/greece.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import EASTER_ORTHODOX, easter
-from dateutil.relativedelta import MO, TU
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAR, MAY, AUG, OCT, DEC
+from holidays.calendars import _get_nth_weekday_from
+from holidays.constants import JAN, MAR, MAY, AUG, OCT, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -60,14 +59,15 @@ def _populate(self, year):
         name = self.tr("Εργατική Πρωτομαγιά")
         name_observed = self.tr("%s (παρατηρήθηκε)")
 
-        self[date(year, MAY, 1)] = name
-        if self.observed and self._is_weekend(year, MAY, 1):
+        dt = date(year, MAY, 1)
+        self[dt] = name
+        if self.observed and self._is_weekend(dt):
             # https://en.wikipedia.org/wiki/Public_holidays_in_Greece
-            labour_day_observed_date = date(year, MAY, 1) + rd(weekday=MO)
+            labour_day_observed_date = _get_nth_weekday_from(1, MON, dt)
             # In 2016 and 2021, Labour Day coincided with other holidays
             # https://www.timeanddate.com/holidays/greece/labor-day
             if self.get(labour_day_observed_date):
-                labour_day_observed_date += rd(weekday=TU)
+                labour_day_observed_date += td(days=+1)
             self[labour_day_observed_date] = name_observed % name
 
         # Assumption of Mary.
diff --git a/holidays/countries/honduras.py b/holidays/countries/honduras.py
index 992eafc26..93c4c3edd 100644
--- a/holidays/countries/honduras.py
+++ b/holidays/countries/honduras.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import WE
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, APR, MAY, SEP, OCT, DEC
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, APR, MAY, SEP, OCT, DEC, WED
 from holidays.holiday_base import HolidayBase
 
 
@@ -67,7 +66,7 @@ def _populate(self, year):
             # Morazan Weekend
             # (First Wednesday of October from 12 noon to Saturday 12 noon)
             holiday_name = "Semana Morazánica [Morazan Weekend]"
-            first_wednesday = date(year, OCT, 1) + rd(weekday=WE(+1))
+            first_wednesday = _get_nth_weekday_of_month(1, WED, OCT, year)
             self[first_wednesday] = holiday_name
             self[first_wednesday + td(days=+1)] = holiday_name
             self[first_wednesday + td(days=+2)] = holiday_name
diff --git a/holidays/countries/hongkong.py b/holidays/countries/hongkong.py
index f6e5228be..2c419e5ad 100644
--- a/holidays/countries/hongkong.py
+++ b/holidays/countries/hongkong.py
@@ -13,12 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, APR, MAY, JUN, JUL, AUG, SEP, OCT, DEC
+from holidays.calendars import _ChineseLuniSolar, _get_nth_weekday_of_month
+from holidays.constants import JAN, APR, MAY, JUN, JUL, AUG, SEP, OCT, DEC, MON
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _ChineseLuniSolar
 
 
 class HongKong(HolidayBase):
@@ -222,12 +220,13 @@ def _populate(self, year):
         # Previous holidays
         if 1952 <= year <= 1997:
             # Queen's Birthday (June 2nd Monday)
-            dt = date(year, JUN, 1) + rd(weekday=MO(+2))
-            self[dt] = "Queen's Birthday"
+            self[
+                _get_nth_weekday_of_month(2, MON, JUN, year)
+            ] = "Queen's Birthday"
 
         if year <= 1996:
             # Anniversary of the liberation of Hong Kong (August last Monday)
-            dt = date(year, AUG, 31) + rd(weekday=MO(-1))
+            dt = _get_nth_weekday_of_month(-1, MON, AUG, year)
             self[dt] = "Anniversary of the liberation of Hong Kong"
 
             # Anniversary of the victory in the Second Sino-Japanese War
diff --git a/holidays/countries/iceland.py b/holidays/countries/iceland.py
index 85203fcfd..99dc05dc0 100644
--- a/holidays/countries/iceland.py
+++ b/holidays/countries/iceland.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO, TH
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, APR, MAY, JUN, AUG, DEC
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
+from holidays.constants import JAN, APR, MAY, JUN, AUG, DEC, MON, THU
 from holidays.holiday_base import HolidayBase
 
 
@@ -38,7 +37,9 @@ def _populate(self, year):
         self[easter_date + td(days=-2)] = "Föstudagurinn langi"
         self[easter_date] = "Páskadagur"
         self[easter_date + td(days=+1)] = "Annar í páskum"
-        self[date(year, APR, 19) + rd(weekday=TH(+1))] = "Sumardagurinn fyrsti"
+        self[
+            _get_nth_weekday_from(1, THU, date(year, APR, 19))
+        ] = "Sumardagurinn fyrsti"
         self[date(year, MAY, 1)] = "Verkalýðsdagurinn"
         self[easter_date + td(days=+39)] = "Uppstigningardagur"
         self[easter_date + td(days=+49)] = "Hvítasunnudagur"
@@ -46,7 +47,7 @@ def _populate(self, year):
         self[date(year, JUN, 17)] = "Þjóðhátíðardagurinn"
         # First Monday of August
         self[
-            date(year, AUG, 1) + rd(weekday=MO(+1))
+            _get_nth_weekday_of_month(1, MON, AUG, year)
         ] = "Frídagur verslunarmanna"
         self[date(year, DEC, 24)] = "Aðfangadagur"
         self[date(year, DEC, 25)] = "Jóladagur"
diff --git a/holidays/countries/india.py b/holidays/countries/india.py
index be6b953bb..edda02165 100644
--- a/holidays/countries/india.py
+++ b/holidays/countries/india.py
@@ -15,9 +15,9 @@
 
 from dateutil.easter import easter
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, APR, MAY, JUN, AUG, OCT, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class India(HolidayBase):
diff --git a/holidays/countries/indonesia.py b/holidays/countries/indonesia.py
index 13f66df0b..5e7ba5b0b 100644
--- a/holidays/countries/indonesia.py
+++ b/holidays/countries/indonesia.py
@@ -14,10 +14,10 @@
 
 from dateutil.easter import easter
 
+from holidays.calendars import _ChineseLuniSolar, _islamic_to_gre
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
 from holidays.constants import OCT, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _ChineseLuniSolar, _islamic_to_gre
 
 
 class Indonesia(HolidayBase):
diff --git a/holidays/countries/ireland.py b/holidays/countries/ireland.py
index 18bee6b37..194d519b3 100644
--- a/holidays/countries/ireland.py
+++ b/holidays/countries/ireland.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, FEB, MAR, MAY, JUN, AUG, OCT, DEC
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
+from holidays.constants import JAN, FEB, MAR, MAY, JUN, AUG, OCT, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -39,18 +38,19 @@ def _populate(self, year):
 
         # St. Brigid's Day
         if year >= 2023:
-            name = "St. Brigid's Day"
             dt = date(year, FEB, 1)
-            self[dt] = name
-            if self.observed and not self._is_friday(dt):
-                self[dt + rd(weekday=MO)] = name + " (Observed)"
+            self[
+                dt
+                if self._is_friday(dt)
+                else _get_nth_weekday_from(1, MON, dt)
+            ] = "St. Brigid's Day"
 
         # St. Patrick's Day
         name = "St. Patrick's Day"
         dt = date(year, MAR, 17)
         self[dt] = name
         if self.observed and self._is_weekend(dt):
-            self[dt + rd(weekday=MO)] = name + " (Observed)"
+            self[_get_nth_weekday_from(1, MON, dt)] = name + " (Observed)"
 
         # Easter Monday
         self[easter(year) + td(days=+1)] = "Easter Monday"
@@ -61,24 +61,30 @@ def _populate(self, year):
             if year == 1995:
                 dt = date(year, MAY, 8)
             else:
-                dt = date(year, MAY, 1) + rd(weekday=MO)
+                dt = _get_nth_weekday_of_month(1, MON, MAY, year)
             self[dt] = name
 
         # June bank holiday (first Monday in June)
-        self[date(year, JUN, 1) + rd(weekday=MO)] = "June Bank Holiday"
+        self[
+            _get_nth_weekday_of_month(1, MON, JUN, year)
+        ] = "June Bank Holiday"
 
         # Summer bank holiday (first Monday in August)
-        self[date(year, AUG, 1) + rd(weekday=MO)] = "August Bank Holiday"
+        self[
+            _get_nth_weekday_of_month(1, MON, AUG, year)
+        ] = "August Bank Holiday"
 
         # October Bank Holiday (last Monday in October)
-        self[date(year, OCT, 31) + rd(weekday=MO(-1))] = "October Bank Holiday"
+        self[
+            _get_nth_weekday_of_month(-1, MON, OCT, year)
+        ] = "October Bank Holiday"
 
         # Christmas Day
         name = "Christmas Day"
         dt = date(year, DEC, 25)
         self[dt] = name
         if self.observed and self._is_weekend(dt):
-            self[dt + rd(weekday=MO)] = name + " (Observed)"
+            self[_get_nth_weekday_from(1, MON, dt)] = name + " (Observed)"
 
         # St. Stephen's Day
         name = "St. Stephen's Day"
diff --git a/holidays/countries/isle_of_man.py b/holidays/countries/isle_of_man.py
index 8a9d23769..23eef1a08 100644
--- a/holidays/countries/isle_of_man.py
+++ b/holidays/countries/isle_of_man.py
@@ -8,12 +8,11 @@
 #           ryanss <ryanssdev@icloud.com> (c) 2014-2017
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
-from datetime import date
 
-from dateutil.relativedelta import FR
-from dateutil.relativedelta import relativedelta as rd
+from datetime import date
 
-from holidays.constants import JUN, JUL
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JUN, JUL, FRI
 from holidays.holiday_base import HolidayBase
 
 from .united_kingdom import UnitedKingdom
@@ -33,7 +32,7 @@ def _populate(self, year: int) -> None:
 
         # Isle of Man exclusive holidays
         # TT bank holiday (first Friday in June)
-        self[date(year, JUN, 1) + rd(weekday=FR)] = "TT Bank Holiday"
+        self[_get_nth_weekday_of_month(1, FRI, JUN, year)] = "TT Bank Holiday"
 
         # Tynwald Day
         self[date(year, JUL, 5)] = "Tynwald Day"
diff --git a/holidays/countries/italy.py b/holidays/countries/italy.py
index f10269331..ff1d0cf37 100644
--- a/holidays/countries/italy.py
+++ b/holidays/countries/italy.py
@@ -14,11 +14,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import relativedelta as rd
-from dateutil.relativedelta import TU, TH, SU
 
+from holidays.calendars import _get_nth_weekday_of_month
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
-from holidays.constants import OCT, NOV, DEC
+from holidays.constants import OCT, NOV, DEC, TUE, SUN
 from holidays.holiday_base import HolidayBase
 
 
@@ -191,7 +190,7 @@ def _populate(self, year):
                 self[date(year, AUG, 7)] = "San Donato D'Arezzo"
             elif self.subdiv == "AT":
                 self[
-                    date(year, MAY, 1) + rd(weekday=TU)
+                    _get_nth_weekday_of_month(1, TUE, MAY, year)
                 ] = "San Secondo di Asti"  # <--- First Tuesday in May
             elif self.subdiv == "AV":
                 self[date(year, FEB, 14)] = "San Modestino"
@@ -210,7 +209,7 @@ def _populate(self, year):
             elif self.subdiv == "BR":
                 # first Sunday of September
                 self[
-                    date(year, SEP, 1) + rd(weekday=SU)
+                    _get_nth_weekday_of_month(1, SUN, SEP, year)
                 ] = "San Teodoro d'Amasea e San Lorenzo da Brindisi"
             elif self.subdiv == "BS":
                 self[date(year, FEB, 15)] = "Santi Faustino e Giovita"
@@ -218,7 +217,7 @@ def _populate(self, year):
                 self[date(year, DEC, 30)] = "San Ruggero"
             if self.subdiv in {"BT", "Andria"}:
                 self[
-                    date(year, SEP, 1) + rd(weekday=SU(+3))
+                    _get_nth_weekday_of_month(3, SUN, SEP, year)
                 ] = "San Riccardo di Andria"  # <--- Third sunday in September
             if self.subdiv in {"BT", "Trani"}:
                 self[date(year, MAY, 3)] = "San Nicola Pellegrino"
@@ -371,7 +370,7 @@ def _populate(self, year):
                 self[date(year, DEC, 6)] = "San Nicola"
             elif self.subdiv == "SU":
                 self[
-                    date(year, MAY, 1) + rd(weekday=SU(+2)) + rd(weekday=TH)
+                    _get_nth_weekday_of_month(2, SUN, MAY, year) + td(days=+4)
                 ] = "San Ponziano"  # <--- Thursday after second sunday in May
             elif self.subdiv == "SV":
                 self[date(year, MAR, 18)] = "Nostra Signora della Misericordia"
diff --git a/holidays/countries/jamaica.py b/holidays/countries/jamaica.py
index 914ea073b..9fafc0e34 100644
--- a/holidays/countries/jamaica.py
+++ b/holidays/countries/jamaica.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAY, AUG, OCT, DEC
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
+from holidays.constants import JAN, MAY, AUG, OCT, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -44,7 +43,7 @@ def _add_with_observed(hol_date: date, hol_name: str) -> None:
         name = "National Labour Day"
         self[dt] = name
         if self.observed and self._is_weekend(dt):
-            self[dt + rd(weekday=MO)] = f"{name} (Observed)"
+            self[_get_nth_weekday_from(1, MON, dt)] = f"{name} (Observed)"
 
         # Emancipation Day
         if year >= 1998:
@@ -54,7 +53,9 @@ def _add_with_observed(hol_date: date, hol_name: str) -> None:
         _add_with_observed(date(year, AUG, 6), "Independence Day")
 
         # National Heroes Day
-        self[date(year, OCT, 1) + rd(weekday=MO(+3))] = "National Heroes Day"
+        self[
+            _get_nth_weekday_of_month(3, MON, OCT, year)
+        ] = "National Heroes Day"
 
         # Christmas Day
         dt = date(year, DEC, 25)
diff --git a/holidays/countries/japan.py b/holidays/countries/japan.py
index 589003638..16ffbdc51 100644
--- a/holidays/countries/japan.py
+++ b/holidays/countries/japan.py
@@ -9,20 +9,24 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-from datetime import date, datetime
+from datetime import date, datetime, timezone
 from datetime import timedelta as td
 from gettext import gettext as tr
 
-from dateutil import tz
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 from pymeeus.Epoch import Epoch
 from pymeeus.Sun import Sun
 
+from holidays.calendars import _get_nth_weekday_of_month
 from holidays.constants import JAN, FEB, APR, MAY, JUN, JUL, AUG, SEP, OCT
-from holidays.constants import NOV, DEC
+from holidays.constants import NOV, DEC, MON
 from holidays.holiday_base import HolidayBase
 
+# use standard library for timezone
+try:
+    from zoneinfo import ZoneInfo
+except ImportError:  # pragma: no cover
+    from backports.zoneinfo import ZoneInfo  # type: ignore[no-redef]
+
 
 class Japan(HolidayBase):
     """
@@ -55,7 +59,7 @@ def _populate(self, year):
         self[
             date(year, JAN, 15)
             if year <= 1999
-            else date(year, JAN, 1) + rd(weekday=MO(+2))
+            else _get_nth_weekday_of_month(2, MON, JAN, year)
             # Coming of Age Day.
         ] = self.tr("成人の日")
 
@@ -70,8 +74,8 @@ def _populate(self, year):
         # Vernal Equinox Day.
         epoch = Sun.get_equinox_solstice(year, target="spring")
         equinox = map(int, Epoch(epoch).get_full_date())
-        adjusted_date = datetime(*equinox, tzinfo=tz.UTC).astimezone(
-            tz.gettz("Asia/Tokyo")
+        adjusted_date = datetime(*equinox, tzinfo=timezone.utc).astimezone(
+            ZoneInfo("Asia/Tokyo")
         )
         self[adjusted_date.date()] = self.tr("春分の日")
 
@@ -101,7 +105,7 @@ def _populate(self, year):
         elif year == 2021:
             self[date(year, JUL, 22)] = self.tr("海の日")
         elif year >= 2003:
-            self[date(year, JUL, 1) + rd(weekday=MO(+3))] = self.tr("海の日")
+            self[_get_nth_weekday_of_month(3, MON, JUL, year)] = self.tr("海の日")
 
         # Mountain Day.
         if year == 2020:
@@ -115,13 +119,15 @@ def _populate(self, year):
         if 1966 <= year <= 2002:
             self[date(year, SEP, 15)] = self.tr("敬老の日")
         elif year >= 2003:
-            self[date(year, SEP, 1) + rd(weekday=MO(+3))] = self.tr("敬老の日")
+            self[_get_nth_weekday_of_month(3, MON, SEP, year)] = self.tr(
+                "敬老の日"
+            )
 
         # Autumnal Equinox Day.
         epoch = Sun.get_equinox_solstice(year, target="autumn")
         equinox = map(int, Epoch(epoch).get_full_date())
-        adjusted_date = datetime(*equinox, tzinfo=tz.UTC).astimezone(
-            tz.gettz("Asia/Tokyo")
+        adjusted_date = datetime(*equinox, tzinfo=timezone.utc).astimezone(
+            ZoneInfo("Asia/Tokyo")
         )
         self[adjusted_date.date()] = self.tr("秋分の日")
 
@@ -129,13 +135,17 @@ def _populate(self, year):
         if 1966 <= year <= 1999:
             self[date(year, OCT, 10)] = self.tr("体育の日")
         elif 2000 <= year <= 2019:
-            self[date(year, OCT, 1) + rd(weekday=MO(+2))] = self.tr("体育の日")
+            self[_get_nth_weekday_of_month(2, MON, OCT, year)] = self.tr(
+                "体育の日"
+            )
         elif year == 2020:
             self[date(year, JUL, 24)] = self.tr("スポーツの日")
         elif year == 2021:
             self[date(year, JUL, 23)] = self.tr("スポーツの日")
         elif 2022 <= year:
-            self[date(year, OCT, 1) + rd(weekday=MO(+2))] = self.tr("スポーツの日")
+            self[_get_nth_weekday_of_month(2, MON, OCT, year)] = self.tr(
+                "スポーツの日"
+            )
 
         # Culture Day.
         self[date(year, NOV, 3)] = self.tr("文化の日")
diff --git a/holidays/countries/kazakhstan.py b/holidays/countries/kazakhstan.py
index 43f12ee2b..23c669630 100644
--- a/holidays/countries/kazakhstan.py
+++ b/holidays/countries/kazakhstan.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, MAY, JUL, AUG, OCT, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Kazakhstan(HolidayBase):
diff --git a/holidays/countries/kyrgyzstan.py b/holidays/countries/kyrgyzstan.py
index bca66c31c..ed5774cf3 100644
--- a/holidays/countries/kyrgyzstan.py
+++ b/holidays/countries/kyrgyzstan.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, FEB, MAR, APR, MAY, AUG, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Kyrgyzstan(HolidayBase):
diff --git a/holidays/countries/lithuania.py b/holidays/countries/lithuania.py
index 697c56d08..07ae660c0 100644
--- a/holidays/countries/lithuania.py
+++ b/holidays/countries/lithuania.py
@@ -13,9 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import SU
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, FEB, MAR, MAY, JUN, AUG, DEC, SUN, JUL, NOV
 from holidays.holiday_base import HolidayBase
 
 
@@ -31,16 +31,16 @@ def _populate(self, year):
         super()._populate(year)
 
         # New Year's Day
-        self[date(year, 1, 1)] = "Naujieji metai"
+        self[date(year, JAN, 1)] = "Naujieji metai"
 
         # Day of Restoration of the State of Lithuania (1918)
         if year >= 1918:
-            self[date(year, 2, 16)] = "Lietuvos valstybės " "atkūrimo diena"
+            self[date(year, FEB, 16)] = "Lietuvos valstybės " "atkūrimo diena"
 
         # Day of Restoration of Independence of Lithuania
         # (from the Soviet Union, 1990)
         if year >= 1990:
-            self[date(year, 3, 11)] = (
+            self[date(year, MAR, 11)] = (
                 "Lietuvos nepriklausomybės " "atkūrimo diena"
             )
 
@@ -52,47 +52,47 @@ def _populate(self, year):
         self[easter_date + td(days=+1)] = "Velykų antroji diena"
 
         # International Workers' Day
-        self[date(year, 5, 1)] = "Tarptautinė darbo diena"
+        self[date(year, MAY, 1)] = "Tarptautinė darbo diena"
 
         # Mother's day. First Sunday in May
-        self[date(year, 5, 1) + rd(weekday=SU)] = "Motinos diena"
+        self[_get_nth_weekday_of_month(1, SUN, MAY, year)] = "Motinos diena"
 
         # Fathers's day. First Sunday in June
-        self[date(year, 6, 1) + rd(weekday=SU)] = "Tėvo diena"
+        self[_get_nth_weekday_of_month(1, SUN, JUN, year)] = "Tėvo diena"
 
         # St. John's Day [Christian name],
         # Day of Dew [original pagan name]
         if year >= 2003:
-            self[date(year, 6, 24)] = "Joninės, Rasos"
+            self[date(year, JUN, 24)] = "Joninės, Rasos"
 
         # Statehood Day
         if year >= 1991:
-            self[date(year, 7, 6)] = (
+            self[date(year, JUL, 6)] = (
                 "Valstybės (Lietuvos "
                 "karaliaus Mindaugo "
                 "karūnavimo) diena"
             )
 
         # Assumption Day
-        self[date(year, 8, 15)] = (
+        self[date(year, AUG, 15)] = (
             "Žolinė (Švč. Mergelės " "Marijos ėmimo į dangų diena)"
         )
 
         # All Saints' Day
-        self[date(year, 11, 1)] = "Visų šventųjų diena (Vėlinės)"
+        self[date(year, NOV, 1)] = "Visų šventųjų diena (Vėlinės)"
 
         # All Souls' Day
         if year >= 2020:
-            self[date(year, 11, 2)] = "Mirusiųjų atminimo diena (Vėlinės)"
+            self[date(year, NOV, 2)] = "Mirusiųjų atminimo diena (Vėlinės)"
 
         # Christmas Eve
-        self[date(year, 12, 24)] = "Šv. Kūčios"
+        self[date(year, DEC, 24)] = "Šv. Kūčios"
 
         # Christmas 1st day
-        self[date(year, 12, 25)] = "Šv. Kalėdų pirma diena"
+        self[date(year, DEC, 25)] = "Šv. Kalėdų pirma diena"
 
         # Christmas 2nd day
-        self[date(year, 12, 26)] = "Šv. Kalėdų antra diena"
+        self[date(year, DEC, 26)] = "Šv. Kalėdų antra diena"
 
 
 class LT(Lithuania):
diff --git a/holidays/countries/madagascar.py b/holidays/countries/madagascar.py
index ca72631e8..0696a001e 100644
--- a/holidays/countries/madagascar.py
+++ b/holidays/countries/madagascar.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import SU
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAR, MAY, JUN, AUG, NOV, DEC
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, MAR, MAY, JUN, AUG, NOV, DEC, SUN
 from holidays.holiday_base import HolidayBase
 
 
@@ -40,7 +39,7 @@ def _populate(self, year):
         self[date(year, MAR, 29)] = "Fetin'ny mahery fo / Martyrs' Day"
         self[date(year, MAY, 1)] = "Labour Day"
         self[
-            date(year, JUN, 1) + rd(weekday=SU(+3))
+            _get_nth_weekday_of_month(3, SUN, JUN, year)
         ] = "Fetin'ny ray / Father's Day"
 
         if year >= 1960:
@@ -71,7 +70,7 @@ def _populate(self, year):
             easter_date + td(days=+50)
         ] = "Alatsinain'ny pentekosta / Whit Monday"
 
-        dt = date(year, MAY, 31) + rd(weekday=SU(-1))
+        dt = _get_nth_weekday_of_month(-1, SUN, MAY, year)
         if dt == whit_sunday:
             dt += td(days=+7)
         self[dt] = "Fetin'ny Reny / Mother's Day"
diff --git a/holidays/countries/malaysia.py b/holidays/countries/malaysia.py
index 73b370c30..9a74722cb 100644
--- a/holidays/countries/malaysia.py
+++ b/holidays/countries/malaysia.py
@@ -11,16 +11,15 @@
 
 from datetime import date
 from datetime import timedelta as td
-from typing import Iterable, Optional, Union
+from typing import Iterable, Optional, Union, Dict, List
 
 from dateutil.easter import easter
-from dateutil.relativedelta import FR, MO, SA, SU
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _ChineseLuniSolar, _islamic_to_gre
+from holidays.calendars import _get_nth_weekday_of_month
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
-from holidays.constants import OCT, NOV, DEC
+from holidays.constants import OCT, NOV, DEC, MON, FRI, SAT, SUN
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _ChineseLuniSolar, _islamic_to_gre
 
 
 class Malaysia(HolidayBase):
@@ -107,22 +106,26 @@ def __init__(
         )
 
     def _populate(self, year):
-        def _add_holiday(dt: date, hol: str) -> None:
-            if dt.year == year:
-                self[dt] = hol
+        def collect_holiday(hol_date: date, hol_name: str) -> None:
+            if hol_date in holiday_date_names_mapping:
+                holiday_date_names_mapping[hol_date].append(hol_name)
+            else:
+                holiday_date_names_mapping[hol_date] = [hol_name]
 
         super()._populate(year)
 
+        holiday_date_names_mapping: Dict[date, List[str]] = {}
+
         estimated_suffix = "* (*estimated)"
 
         # Chinese New Year (one day in the States of Kelantan and Terengganu,
         # two days in the other States).
         hol_date = self.cnls.lunar_n_y_date(year)
-        self[hol_date] = "Chinese New Year"
+        collect_holiday(hol_date, "Chinese New Year")
         # The second day of Chinese New Year is not a federal holiday in
         # Kelantan and Terengganu. However, it is gazetted as a state holiday
         # in both states, effectively making it a nationwide holiday.
-        self[hol_date + td(days=+1)] = "Chinese New Year Holiday"
+        collect_holiday(hol_date + td(days=+1), "Chinese New Year Holiday")
 
         # Wesak Day.
         # Date of observance is announced yearly
@@ -156,30 +159,30 @@ def _add_holiday(dt: date, hol: str) -> None:
             hol_date = date(year, *dates_obs[year])
         else:
             hol_date = self.cnls.vesak_may_date(year)
-            name += estimated_suffix
-        self[hol_date] = name
+            name = f"{name}{estimated_suffix}"
+        collect_holiday(hol_date, name)
 
         # Labour Day.
-        self[date(year, MAY, 1)] = "Labour Day"
+        collect_holiday(date(year, MAY, 1), "Labour Day")
 
         # Birthday of [His Majesty] the Yang di-Pertuan Agong.
         if year <= 2017:
-            hol_date = date(year, JUN, 1) + rd(weekday=SA)
+            hol_date = _get_nth_weekday_of_month(1, SAT, JUN, year)
         elif year == 2018:
             hol_date = date(2018, SEP, 9)
         elif year == 2020:
             # https://www.nst.com.my/news/nation/2020/03/571660/agongs-birthday-moved-june-6-june-8
             hol_date = date(2020, JUN, 8)
         else:
-            hol_date = date(year, JUN, 1) + rd(weekday=MO)
-        self[hol_date] = "Birthday of SPB Yang di-Pertuan Agong"
+            hol_date = _get_nth_weekday_of_month(1, MON, JUN, year)
+        collect_holiday(hol_date, "Birthday of SPB Yang di-Pertuan Agong")
 
         # Hari Kebangsaan or National Day.
-        self[date(year, AUG, 31)] = "National Day"
+        collect_holiday(date(year, AUG, 31), "National Day")
 
         # Malaysia Day.
         if year >= 2010:
-            self[date(year, SEP, 16)] = "Malaysia Day"
+            collect_holiday(date(year, SEP, 16), "Malaysia Day")
 
         # Deepavali.
         # aka Diwali;
@@ -214,11 +217,11 @@ def _add_holiday(dt: date, hol: str) -> None:
                 hol_date = date(year, *dates_obs[year])
             else:
                 hol_date = self.cnls.s_diwali_date(year)
-                name += estimated_suffix
-            self[hol_date] = name
+                name = f"{name}{estimated_suffix}"
+            collect_holiday(hol_date, name)
 
         # Christmas day.
-        self[date(year, DEC, 25)] = "Christmas Day"
+        collect_holiday(date(year, DEC, 25), "Christmas Day")
 
         # Birthday of the Prophet Muhammad (s.a.w.).
         # a.k.a. Hari Keputeraan Nabi Muhammad (Sabah Act)
@@ -260,7 +263,7 @@ def _add_holiday(dt: date, hol: str) -> None:
                 for date_obs in _islamic_to_gre(year, 3, 12)
             ]
         for hol_date, hol_suffix in hol_dates:
-            self[hol_date] = name + hol_suffix
+            collect_holiday(hol_date, f"{name}{hol_suffix}")
 
         # Hari Raya Puasa (2 days).
         # aka Eid al-Fitr;
@@ -296,11 +299,11 @@ def _add_holiday(dt: date, hol: str) -> None:
                 for date_obs in dates_obs[yr]:
                     hol_dates.append((date(yr, *date_obs), ""))
             else:
-                for date_obs in _islamic_to_gre(year, 10, 1):
+                for date_obs in _islamic_to_gre(yr, 10, 1):
                     hol_dates.append((date_obs, estimated_suffix))
         for hol_date, hol_suffix in hol_dates:
-            _add_holiday(hol_date, f"{name}{hol_suffix}")
-            _add_holiday(
+            collect_holiday(hol_date, f"{name}{hol_suffix}")
+            collect_holiday(
                 hol_date + td(days=+1),
                 f"Second day of {name}{hol_suffix}",
             )
@@ -341,16 +344,18 @@ def _add_holiday(dt: date, hol: str) -> None:
                 for date_obs in dates_obs[yr]:
                     hol_dates.append((date(yr, *date_obs), ""))
             else:
-                for date_obs in _islamic_to_gre(year, 12, 10):
+                for date_obs in _islamic_to_gre(yr, 12, 10):
                     hol_dates.append((date_obs, estimated_suffix))
         for hol_date, hol_suffix in hol_dates:
-            _add_holiday(hol_date, f"{name}{hol_suffix}")
+            collect_holiday(hol_date, f"{name}{hol_suffix}")
             if self.subdiv == "TRG":
                 # Arafat Day is one day before Eid al-Adha
-                _add_holiday(hol_date + td(days=-1), f"Arafat Day{hol_suffix}")
+                collect_holiday(
+                    hol_date + td(days=-1), f"Arafat Day{hol_suffix}"
+                )
             if self.subdiv in {"KDH", "KTN", "PLS", "TRG"}:
                 # Second day
-                _add_holiday(
+                collect_holiday(
                     hol_date + td(days=+1),
                     f"{name} Holiday{hol_suffix}",
                 )
@@ -360,19 +365,21 @@ def _add_holiday(dt: date, hol: str) -> None:
         # ---------------------------------------------------------#
         if self.subdiv == "SWK":
             # Dayak Festival Day (the first day of June) and the following day.
-            self[date(year, JUN, 1)] = "Gawai Dayak"
-            self[date(year, JUN, 2)] = "Gawai Dayak (Second day)"
+            collect_holiday(date(year, JUN, 1), "Gawai Dayak")
+            collect_holiday(date(year, JUN, 2), "Gawai Dayak (Second day)")
 
             # The first day of May—Worker’s Celebration Day.
 
-            # Birthday of Tuan Yang Terutama Yang di-Pertua Negeri Sarawak (the
-            # second Saturday of September).
-            second_sat_oct = date(year, OCT, 1) + rd(weekday=SA(+2))
-            self[second_sat_oct] = "Birthday of the Governor of Sarawak"
+            # Birthday of Tuan Yang Terutama Yang di-Pertua Negeri Sarawak
+            # (the second Saturday of October).
+            collect_holiday(
+                _get_nth_weekday_of_month(2, SAT, OCT, year),
+                "Birthday of the Governor of Sarawak",
+            )
 
             # Sarawak Independence Day
             if year >= 2017:
-                self[date(year, JUL, 22)] = "Sarawak Day"
+                collect_holiday(date(year, JUL, 22), "Sarawak Day")
 
         # New Year's Day
         if self.subdiv in {
@@ -388,7 +395,7 @@ def _add_holiday(dt: date, hol: str) -> None:
             "SGR",
             "SWK",
         }:
-            self[date(year, JAN, 1)] = "New Year's Day"
+            collect_holiday(date(year, JAN, 1), "New Year's Day")
 
         # Isra and Mi'raj.
         if self.subdiv in {"KDH", "NSN", "PLS"} or (
@@ -429,7 +436,7 @@ def _add_holiday(dt: date, hol: str) -> None:
                     for date_obs in _islamic_to_gre(year, 7, 27)
                 ]
             for hol_date, hol_suffix in hol_dates:
-                self[hol_date] = name + hol_suffix
+                collect_holiday(hol_date, f"{name}{hol_suffix}")
 
         # Beginning of Ramadan.
         if self.subdiv in {"JHR", "KDH", "MLK"}:
@@ -468,7 +475,7 @@ def _add_holiday(dt: date, hol: str) -> None:
                     for date_obs in _islamic_to_gre(year, 9, 1)
                 ]
             for hol_date, hol_suffix in hol_dates:
-                self[hol_date] = name + hol_suffix
+                collect_holiday(hol_date, f"{name}{hol_suffix}")
 
         # Nuzul Al-Quran Day.
         if self.subdiv in {
@@ -518,7 +525,7 @@ def _add_holiday(dt: date, hol: str) -> None:
                     for date_obs in _islamic_to_gre(year, 9, 17)
                 ]
             for hol_date, hol_suffix in hol_dates:
-                self[hol_date] = name + hol_suffix
+                collect_holiday(hol_date, f"{name}{hol_suffix}")
 
         # Thaipusam.
         # An annual Hindu festival observed on the day of the first full moon
@@ -541,70 +548,77 @@ def _add_holiday(dt: date, hol: str) -> None:
                 hol_date = date(year, *dates_obs[year])
             else:
                 hol_date = self.cnls.thaipusam_date(year)
-                name += estimated_suffix
-            self[hol_date] = name
+                name = f"{name}{estimated_suffix}"
+            collect_holiday(hol_date, name)
 
         # Federal Territory Day.
         if self.subdiv in {"KUL", "LBN", "PJY"} and year >= 1974:
-            self[date(year, FEB, 1)] = "Federal Territory Day"
+            collect_holiday(date(year, FEB, 1), "Federal Territory Day")
 
         # State holidays (single state)
 
         if self.subdiv == "MLK":
             if year >= 1989:
-                self[
-                    date(year, APR, 15)
-                ] = "Declaration of Malacca as a Historical City"
-            if year >= 2020:
-                hol_date = date(year, AUG, 24)
-            else:
-                hol_date = date(year, OCT, 1) + rd(weekday=FR(+2))
-            self[hol_date] = "Birthday of the Governor of Malacca"
+                collect_holiday(
+                    date(year, APR, 15),
+                    "Declaration of Malacca as a Historical City",
+                )
 
-        elif self.subdiv == "NSN":
-            if year >= 2009:
-                self[
-                    date(year, JAN, 14)
-                ] = "Birthday of the Sultan of Negeri Sembilan"
+            collect_holiday(
+                date(year, AUG, 24)
+                if year >= 2020
+                else _get_nth_weekday_of_month(2, FRI, OCT, year),
+                "Birthday of the Governor of Malacca",
+            )
 
-        elif self.subdiv == "PHG":
-            if year >= 2020:
-                hol_date = date(year, MAY, 22)
-            else:
-                hol_date = date(year, MAY, 7)
-            self[hol_date] = "Hari Hol of Pahang"
+        elif self.subdiv == "NSN" and year >= 2009:
+            collect_holiday(
+                date(year, JAN, 14),
+                "Birthday of the Sultan of Negeri Sembilan",
+            )
 
-            if year >= 2019:
-                hol_date = date(year, JUL, 30)
-            elif 1975 <= year <= 2018:
-                hol_date = date(year, OCT, 24)
-            self[hol_date] = "Birthday of the Sultan of Pahang"
+        elif self.subdiv == "PHG" and year >= 1975:
+            collect_holiday(
+                date(year, MAY, 22) if year >= 2021 else date(year, MAY, 7),
+                "Hari Hol of Pahang",
+            )
+
+            collect_holiday(
+                date(year, JUL, 30) if year >= 2019 else date(year, OCT, 24),
+                "Birthday of the Sultan of Pahang",
+            )
 
         elif self.subdiv == "PNG":
             if year >= 2009:
-                self[date(year, JUL, 7)] = "George Town Heritage Day"
-            second_sat_jul = date(year, JUL, 1) + rd(weekday=SA(+2))
-            self[second_sat_jul] = "Birthday of the Governor of Penang"
+                collect_holiday(date(year, JUL, 7), "George Town Heritage Day")
 
-        elif self.subdiv == "PLS":
-            if year >= 2018:
-                hol_date = date(year, JUL, 17)
-            elif year >= 2000:
-                hol_date = date(year, MAY, 17)
-            self[hol_date] = "Birthday of The Raja of Perlis"
+            collect_holiday(
+                _get_nth_weekday_of_month(2, SAT, JUL, year),
+                "Birthday of the Governor of Penang",
+            )
+
+        elif self.subdiv == "PLS" and year >= 2000:
+            collect_holiday(
+                date(year, JUL, 17) if year >= 2018 else date(year, MAY, 17),
+                "Birthday of The Raja of Perlis",
+            )
 
         elif self.subdiv == "SGR":
-            self[date(year, DEC, 11)] = "Birthday of The Sultan of Selangor"
+            collect_holiday(
+                date(year, DEC, 11), "Birthday of The Sultan of Selangor"
+            )
 
-        elif self.subdiv == "TRG":
-            if year >= 2000:
-                self[date(year, MAR, 4)] = (
+        elif self.subdiv == "TRG" and year >= 2000:
+            collect_holiday(
+                date(year, MAR, 4),
+                (
                     "Anniversary of the Installation "
                     "of the Sultan of Terengganu"
-                )
-                self[
-                    date(year, APR, 26)
-                ] = "Birthday of the Sultan of Terengganu"
+                ),
+            )
+            collect_holiday(
+                date(year, APR, 26), "Birthday of the Sultan of Terengganu"
+            )
 
         # Check for holidays that fall on a Sunday and
         # implement Section 3 of Malaysian Holidays Act:
@@ -614,29 +628,30 @@ def _add_holiday(dt: date, hol: str) -> None:
         # then the day following shall be a public holiday"
         # In Johor and Kedah it's Friday -> Sunday,
         # in Kelantan and Terengganu it's Saturday -> Sunday
-        for hol_date, hol_name in list(self.items()):
-            if hol_date.year != year:
-                continue
-            in_lieu_date = None
-            if self._is_friday(hol_date) and self.subdiv in {"JHR", "KDH"}:
-                in_lieu_date = hol_date + td(days=+2)
-            elif self._is_saturday(hol_date) and self.subdiv in {
-                "KTN",
-                "TRG",
-            }:
-                in_lieu_date = hol_date + td(days=+1)
-            elif self._is_sunday(hol_date) and self.subdiv not in {
-                "JHR",
-                "KDH",
-                "KTN",
-                "TRG",
-            }:
-                in_lieu_date = hol_date + td(days=+1)
-            if not in_lieu_date:
-                continue
-            while in_lieu_date.year == year and in_lieu_date in self:
-                in_lieu_date += td(days=+1)
-            _add_holiday(in_lieu_date, f"{hol_name} [In lieu]")
+        if self.observed:
+            weekday_observed_days = (
+                (FRI, +2)
+                if self.subdiv in {"JHR", "KDH"}
+                else (
+                    (SAT, +1) if self.subdiv in {"KTN", "TRG"} else (SUN, +1)
+                )
+            )
+            hol_dates = list(holiday_date_names_mapping.keys())
+            for hol_date, hol_names in sorted(
+                holiday_date_names_mapping.items()
+            ):
+                if hol_date.weekday() == weekday_observed_days[0]:
+                    in_lieu_date = hol_date + td(days=weekday_observed_days[1])
+                    while in_lieu_date in hol_dates:
+                        in_lieu_date += td(days=+1)
+                    for hol_name in hol_names:
+                        collect_holiday(in_lieu_date, f"{hol_name} [In lieu]")
+                    hol_dates.append(in_lieu_date)
+
+        for hol_date, hol_names in holiday_date_names_mapping.items():
+            if hol_date.year == year:
+                for hol_name in hol_names:
+                    self[hol_date] = hol_name
 
         # The last two days in May (Pesta Kaamatan).
         # (Sarawak Act)
@@ -749,29 +764,30 @@ def _add_holiday(dt: date, hol: str) -> None:
                 for hol_date, hol_suffix in hol_dates:
                     self[hol_date] = name + hol_suffix
 
-        elif self.subdiv == "KDH":
-            if year >= 2020:
-                third_sun_jun = date(year, JUN, 1) + rd(weekday=SU(+3))
-                self[third_sun_jun] = "Birthday of The Sultan of Kedah"
+        elif self.subdiv == "KDH" and year >= 2020:
+            self[
+                _get_nth_weekday_of_month(3, SUN, JUN, year)
+            ] = "Birthday of The Sultan of Kedah"
 
-        elif self.subdiv == "KTN":
-            if year >= 2010:
-                name = "Birthday of the Sultan of Kelantan"
-                self[date(year, NOV, 11)] = name
-                self[date(year, NOV, 12)] = name
+        elif self.subdiv == "KTN" and year >= 2010:
+            name = "Birthday of the Sultan of Kelantan"
+            self[date(year, NOV, 11)] = name
+            self[date(year, NOV, 12)] = name
 
         elif self.subdiv == "PRK":
             # This Holiday used to be on 27th until 2017
             # https://www.officeholidays.com/holidays/malaysia/birthday-of-the-sultan-of-perak  # noqa: E501
-            if year >= 2018:
-                first_fri_nov = date(year, NOV, 1) + rd(weekday=FR)
-                self[first_fri_nov] = "Birthday of the Sultan of Perak"
-            else:
-                self[date(year, NOV, 27)] = "Birthday of the Sultan of Perak"
+            self[
+                _get_nth_weekday_of_month(1, FRI, NOV, year)
+                if year >= 2018
+                else date(year, NOV, 27)
+            ] = "Birthday of the Sultan of Perak"
 
         elif self.subdiv == "SBH":
-            first_sat_oct = date(year, OCT, 1) + rd(weekday=SA)
-            self[first_sat_oct] = "Birthday of the Governor of Sabah"
+            self[
+                _get_nth_weekday_of_month(1, SAT, OCT, year)
+            ] = "Birthday of the Governor of Sabah"
+
             if year >= 2019:
                 self[date(year, DEC, 24)] = "Christmas Eve"
 
diff --git a/holidays/countries/marshall_islands.py b/holidays/countries/marshall_islands.py
index 7e012566f..8d4415a54 100644
--- a/holidays/countries/marshall_islands.py
+++ b/holidays/countries/marshall_islands.py
@@ -8,15 +8,15 @@
 #           ryanss <ryanssdev@icloud.com> (c) 2014-2017
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
+
 import warnings
 from datetime import date
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import FR
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAR, MAY, JUL, SEP, NOV, DEC
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, MAR, MAY, JUL, SEP, NOV, DEC, FRI
 from holidays.holiday_base import HolidayBase
 
 
@@ -72,25 +72,25 @@ def _populate(self, year):
         )
 
         # Good Friday
-        self[easter(year) + td(days=-2)] = "Good Friday Friday"
+        self[easter(year) + td(days=-2)] = "Good Friday"
 
         # Constitution Day
         self[date(year, MAY, 1)] = "Constitution Day"
 
         # Fisherman's Day
-        self[date(year, JUL, 1) + rd(weekday=FR)] = "Fisherman's Day"
+        self[_get_nth_weekday_of_month(1, FRI, JUL, year)] = "Fisherman's Day"
 
         # Dri-jerbal Day
-        self[date(year, SEP, 1) + rd(weekday=FR)] = "Dri-jerbal Day"
+        self[_get_nth_weekday_of_month(1, FRI, SEP, year)] = "Dri-jerbal Day"
 
         # Manit Day
-        self[date(year, SEP, 30) + rd(weekday=FR(-1))] = "Manit Day"
+        self[_get_nth_weekday_of_month(-1, FRI, SEP, year)] = "Manit Day"
 
         # President's Day
         self._add_with_observed(date(year, NOV, 17), "President's Day")
 
         # Gospel Day
-        self[date(year, DEC, 1) + rd(weekday=FR)] = "Gospel Day"
+        self[_get_nth_weekday_of_month(1, FRI, DEC, year)] = "Gospel Day"
 
         # Christmas Day
         self._add_with_observed(date(year, DEC, 25), "Christmas Day")
diff --git a/holidays/countries/mexico.py b/holidays/countries/mexico.py
index b7275e08d..4fea6e376 100644
--- a/holidays/countries/mexico.py
+++ b/holidays/countries/mexico.py
@@ -10,94 +10,73 @@
 #  License: MIT (see LICENSE file)
 
 from datetime import date
-from datetime import timedelta as td
 
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
-
-from holidays.constants import JAN, FEB, MAR, MAY, SEP, NOV, DEC
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, FEB, MAR, MAY, SEP, NOV, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
 class Mexico(HolidayBase):
-    country = "MX"
+    """
+    References:
+    - https://en.wikipedia.org/wiki/Public_holidays_in_Mexico
+    - https://es.wikipedia.org/wiki/Anexo:D%C3%ADas_festivos_en_M%C3%A9xico
+    - https://www.gob.mx/cms/uploads/attachment/file/156203/1044_Ley_Federal_del_Trabajo.pdf  # noqa: E501
+    - http://www.diputados.gob.mx/LeyesBiblio/ref/lft/LFT_orig_01abr70_ima.pdf
+    """
 
-    def _add_with_observed(self, holiday: date, name: str):
-        self[holiday] = name
-        if self.observed and self._is_saturday(holiday):
-            self[holiday + td(days=-1)] = name + " (Observed)"
-        elif self.observed and self._is_sunday(holiday):
-            self[holiday + td(days=+1)] = name + " (Observed)"
+    country = "MX"
 
     def _populate(self, year):
         super()._populate(year)
 
         # New Year's Day
-        name = "Año Nuevo [New Year's Day]"
-        dt = date(year, JAN, 1)
-        self[dt] = name
-        if self.observed and self._is_sunday(dt):
-            self[dt + td(days=+1)] = name + " (Observed)"
-        # The next year's observed New Year's Day can be in this year
-        # when it falls on a Friday (Jan 1st is a Saturday)
-        if self.observed and self._is_friday(year, DEC, 31):
-            self[date(year, DEC, 31)] = name + " (Observed)"
+        self[date(year, JAN, 1)] = "Año Nuevo [New Year's Day]"
 
         # Constitution Day
-        name = "Día de la Constitución [Constitution Day]"
-        if self.observed and year >= 2007:
-            self[date(year, FEB, 1) + rd(weekday=MO(+1))] = (
-                name + " (Observed)"
-            )
-
         if year >= 1917:
-            self[date(year, FEB, 5)] = name
+            self[
+                _get_nth_weekday_of_month(1, MON, FEB, year)
+                if year >= 2006
+                else date(year, FEB, 5)
+            ] = "Día de la Constitución [Constitution Day]"
 
         # Benito Juárez's birthday
-        name = "Natalicio de Benito Juárez [Benito Juárez's birthday]"
-        if self.observed and year >= 2007:
-            self[date(year, MAR, 1) + rd(weekday=MO(+3))] = (
-                name + " (Observed)"
-            )
-
         if year >= 1917:
-            self[date(year, MAR, 21)] = name
-
-        # Labor Day
+            self[
+                _get_nth_weekday_of_month(3, MON, MAR, year)
+                # no 2006 due to celebration of the 200th anniversary
+                # of Benito Juárez in 2006
+                if year >= 2007
+                else date(year, MAR, 21)
+            ] = "Natalicio de Benito Juárez [Benito Juárez's birthday]"
+
+        # Labour Day
         if year >= 1923:
-            name = "Día del Trabajo [Labour Day]"
-            dt = date(year, MAY, 1)
-            self._add_with_observed(dt, name)
+            self[date(year, MAY, 1)] = "Día del Trabajo [Labour Day]"
 
         # Independence Day
-        name = "Día de la Independencia [Independence Day]"
-        dt = date(year, SEP, 16)
-        self._add_with_observed(dt, name)
+        self[
+            date(year, SEP, 16)
+        ] = "Día de la Independencia [Independence Day]"
 
         # Revolution Day
-        name = "Día de la Revolución [Revolution Day]"
-        if self.observed and year >= 2007:
-            self[date(year, NOV, 1) + rd(weekday=MO(+3))] = (
-                name + " (Observed)"
-            )
-
         if year >= 1917:
-            self[date(year, NOV, 20)] = name
-
-        # Change of Federal Government
-        # Every six years--next observance 2018
-        if year >= 1970 and (2096 - year) % 6 == 0:
-            name = (
+            self[
+                _get_nth_weekday_of_month(3, MON, NOV, year)
+                if year >= 2006
+                else date(year, NOV, 20)
+            ] = "Día de la Revolución [Revolution Day]"
+
+        # Change of Federal Government, every six years
+        if year >= 1970 and (year - 1970) % 6 == 0:
+            self[date(year, DEC, 1)] = (
                 "Transmisión del Poder Ejecutivo Federal"
                 " [Change of Federal Government]"
             )
-            dt = date(year, DEC, 1)
-            self._add_with_observed(dt, name)
 
         # Christmas
-        name = "Navidad [Christmas]"
-        dt = date(year, DEC, 25)
-        self._add_with_observed(dt, name)
+        self[date(year, DEC, 25)] = "Navidad [Christmas Day]"
 
 
 class MX(Mexico):
diff --git a/holidays/countries/monaco.py b/holidays/countries/monaco.py
index eb8b3a055..2409a36d8 100644
--- a/holidays/countries/monaco.py
+++ b/holidays/countries/monaco.py
@@ -11,6 +11,7 @@
 
 from datetime import date
 from datetime import timedelta as td
+from gettext import gettext as tr
 
 from dateutil.easter import easter
 
@@ -25,70 +26,64 @@ class Monaco(HolidayBase):
     """
 
     country = "MC"
+    default_language = "fr"
     special_holidays = {
-        2015: ((JAN, 7, "Jour férié [Public holiday]"),),
+        2015: ((JAN, 7, tr("Jour férié")),),
     }
 
     def _populate(self, year):
         def _add_with_observed(hol_date: date, hol_name: str) -> None:
             self[hol_date] = hol_name
             if self.observed and self._is_sunday(hol_date):
-                self[hol_date + td(days=+1)] = f"{hol_name} (Observed)"
+                self[hol_date + td(days=+1)] = (
+                    self.tr("%s (Observé)") % hol_name
+                )
 
         super()._populate(year)
 
         # New Year's Day
-        _add_with_observed(
-            date(year, JAN, 1), "Le jour de l'An [New Year's Day]"
-        )
+        _add_with_observed(date(year, JAN, 1), self.tr("Le jour de l'An"))
 
         # Saint Dévote's Day
-        self[date(year, JAN, 27)] = "La Sainte Dévote [Saint Dévote's Day]"
+        self[date(year, JAN, 27)] = self.tr("La Sainte Dévote")
 
         easter_date = easter(year)
 
         # Easter Monday
-        self[easter_date + td(days=+1)] = "Le lundi de Pâques [Easter Monday]"
+        self[easter_date + td(days=+1)] = self.tr("Le lundi de Pâques")
 
         # Labour Day
-        _add_with_observed(
-            date(year, MAY, 1), "Fête de la Travaille [Labour Day]"
-        )
+        _add_with_observed(date(year, MAY, 1), self.tr("Fête de la Travaille"))
 
         # Ascension's Day
-        self[easter_date + td(days=+39)] = "L'Ascension [Ascension's Day]"
+        self[easter_date + td(days=+39)] = self.tr("L'Ascension")
 
         # Whit Monday
-        self[
-            easter_date + td(days=+50)
-        ] = "Le lundi de Pentecôte [Whit Monday]"
+        self[easter_date + td(days=+50)] = self.tr("Le lundi de Pentecôte")
 
         # Corpus Christi
-        self[easter_date + td(days=+60)] = "La Fête Dieu [Corpus Christi]"
+        self[easter_date + td(days=+60)] = self.tr("La Fête Dieu")
 
-        # Assumption's Day
         _add_with_observed(
-            date(year, AUG, 15), "L'Assomption de Marie [Assumption's Day]"
+            date(year, AUG, 15),
+            # Assumption's Day
+            self.tr("L'Assomption de Marie"),
         )
 
         # All Saints' Day
-        _add_with_observed(
-            date(year, NOV, 1), "La Toussaint [All Saints' Day]"
-        )
+        _add_with_observed(date(year, NOV, 1), self.tr("La Toussaint"))
 
         # Prince's Day
-        _add_with_observed(
-            date(year, NOV, 19), "La Fête du Prince [Prince's Day]"
-        )
+        _add_with_observed(date(year, NOV, 19), self.tr("La Fête du Prince"))
 
-        # Immaculate Conception's Day
         dt = date(year, DEC, 8)
         if year >= 2019 and self._is_sunday(dt):
             dt += td(days=+1)
-        self[dt] = "L'Immaculée Conception [Immaculate Conception's Day]"
+        # Immaculate Conception's Day
+        self[dt] = self.tr("L'Immaculée Conception")
 
         # Christmas Day
-        _add_with_observed(date(year, DEC, 25), "Noël [Christmas Day]")
+        _add_with_observed(date(year, DEC, 25), self.tr("Noël"))
 
 
 class MC(Monaco):
diff --git a/holidays/countries/morocco.py b/holidays/countries/morocco.py
index 80d4dc480..2dc2ec4d7 100644
--- a/holidays/countries/morocco.py
+++ b/holidays/countries/morocco.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, MAY, JUL, AUG, NOV
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Morocco(HolidayBase):
diff --git a/holidays/countries/new_zealand.py b/holidays/countries/new_zealand.py
index 6a4b057af..c76295728 100644
--- a/holidays/countries/new_zealand.py
+++ b/holidays/countries/new_zealand.py
@@ -13,10 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO, TU, WE
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, FEB, MAR, APR, JUN, JUL, SEP, OCT, NOV, DEC
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
+from holidays.constants import JAN, FEB, MAR, APR, JUN, JUL, SEP, OCT, NOV
+from holidays.constants import DEC, MON, TUE, WED
 from holidays.holiday_base import HolidayBase
 
 
@@ -64,15 +64,13 @@ class NewZealand(HolidayBase):
     ]
 
     def _get_nearest_monday(self, dt: date) -> date:
-        return (
-            dt + rd(weekday=MO(-1))
-            if not self._is_friday(dt) and not self._is_weekend(dt)
-            else dt + rd(weekday=MO)
+        return _get_nth_weekday_from(
+            1 if self._is_friday(dt) or self._is_weekend(dt) else -1, MON, dt
         )
 
     def _add_observed(self, dt: date) -> None:
         if self.observed and self._is_weekend(dt):
-            obs_date = dt + rd(weekday=MO)
+            obs_date = _get_nth_weekday_from(1, MON, dt)
             if self.get(obs_date):
                 obs_date += td(days=+1)
             self[obs_date] = f"{self[dt]} (Observed)"
@@ -133,7 +131,9 @@ def _populate(self, year):
             if year == 1952:
                 self[date(year, JUN, 2)] = name  # Elizabeth II
             elif year >= 1938:
-                self[date(year, JUN, 1) + rd(weekday=MO)] = name  # EII & GVI
+                self[
+                    _get_nth_weekday_of_month(1, MON, JUN, year)
+                ] = name  # EII & GVI
             elif year == 1937:
                 self[date(year, JUN, 9)] = name  # George VI
             elif year == 1936:
@@ -184,9 +184,9 @@ def _populate(self, year):
         # Labour Day
         name = "Labour Day"
         if year >= 1910:
-            self[date(year, OCT, 1) + rd(weekday=MO(+4))] = name
+            self[_get_nth_weekday_of_month(4, MON, OCT, year)] = name
         elif year >= 1900:
-            self[date(year, OCT, 1) + rd(weekday=WE(+2))] = name
+            self[_get_nth_weekday_of_month(2, WED, OCT, year)] = name
 
         # Christmas Day
         dec25 = date(year, DEC, 25)
@@ -210,12 +210,12 @@ def _populate(self, year):
 
         elif self.subdiv in {"New Plymouth", "Taranaki", "TKI"}:
             self[
-                date(year, MAR, 1) + rd(weekday=MO(+2))
+                _get_nth_weekday_of_month(2, MON, MAR, year)
             ] = "Taranaki Anniversary Day"
 
         elif self.subdiv in {"Hawke's Bay", "HKB"}:
             self[
-                (date(year, OCT, 1) + rd(weekday=MO(+4)) + td(days=-3))
+                _get_nth_weekday_of_month(4, MON, OCT, year) + td(days=-3)
             ] = "Hawke's Bay Anniversary Day"
 
         elif self.subdiv in {"WGN", "Wellington"}:
@@ -225,7 +225,7 @@ def _populate(self, year):
 
         elif self.subdiv in {"Marlborough", "MBH"}:
             self[
-                (date(year, OCT, 1) + rd(weekday=MO(+4)) + td(days=+7))
+                _get_nth_weekday_of_month(4, MON, OCT, year) + td(days=+7)
             ] = "Marlborough Anniversary Day"
 
         elif self.subdiv in {"Nelson", "NSN"}:
@@ -235,12 +235,12 @@ def _populate(self, year):
 
         elif self.subdiv in {"CAN", "Canterbury"}:
             self[
-                (date(year, NOV, 1) + rd(weekday=TU) + td(days=+10))
+                _get_nth_weekday_of_month(1, TUE, NOV, year) + td(days=+10)
             ] = "Canterbury Anniversary Day"
 
         elif self.subdiv in {"South Canterbury", "STC"}:
             self[
-                (date(year, SEP, 1) + rd(weekday=MO(+4)))
+                _get_nth_weekday_of_month(4, MON, SEP, year)
             ] = "South Canterbury Anniversary Day"
 
         elif self.subdiv in {"WTC", "West Coast", "WTL", "Westland"}:
diff --git a/holidays/countries/nigeria.py b/holidays/countries/nigeria.py
index 1eca09322..7df8d30d9 100644
--- a/holidays/countries/nigeria.py
+++ b/holidays/countries/nigeria.py
@@ -11,12 +11,13 @@
 
 from datetime import date
 from datetime import timedelta as td
+from typing import Dict, List
 
 from dateutil.easter import easter
 
-from holidays.constants import JAN, MAY, JUN, OCT, DEC
+from holidays.calendars import _islamic_to_gre
+from holidays.constants import JAN, FEB, MAY, JUN, OCT, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Nigeria(HolidayBase):
@@ -25,82 +26,98 @@ class Nigeria(HolidayBase):
     """
 
     country = "NG"
+    special_holidays = {
+        2019: (
+            (FEB, 22, "Public Holiday for Elections"),
+            (MAY, 29, "Presidential Inauguration Day"),
+        ),
+    }
 
     def _populate(self, year):
-        def _add_holiday(dt: date, hol: str) -> None:
-            """Only add if in current year; prevents adding holidays across
-            years (handles multi-day Islamic holidays that straddle
-            Gregorian years).
-            """
-            if dt.year == year:
-                self[dt] = hol
+        def collect_holiday(hol_date: date, hol_name: str) -> None:
+            if hol_date in holiday_date_names_mapping:
+                holiday_date_names_mapping[hol_date].append(hol_name)
+            else:
+                holiday_date_names_mapping[hol_date] = [hol_name]
 
         if year <= 1978:
             return None
 
         super()._populate(year)
 
+        holiday_date_names_mapping: Dict[date, List[str]] = {}
+
         # New Year's Day
-        self[date(year, JAN, 1)] = "New Year's day"
+        collect_holiday(date(year, JAN, 1), "New Year's Day")
 
-        # Calculate Easter for given year
-        # followed by easter related holidays
         easter_date = easter(year)
-        self[easter_date + td(days=-2)] = "Good Friday"
-        self[easter_date + td(days=+1)] = "Easter Monday"
+        collect_holiday(easter_date + td(days=-2), "Good Friday")
+        collect_holiday(easter_date + td(days=+1), "Easter Monday")
 
         # Worker's day
         if year >= 1981:
-            self[date(year, MAY, 1)] = "Workers' day"
+            collect_holiday(date(year, MAY, 1), "Workers' Day")
+
+        # Democracy day moved around after its inception in 2000
+        # Initally it fell on May 29th
+        # In 2018 it was announced that the holiday
+        # will move to June 12th from 2019
+        if year >= 2000:
+            collect_holiday(
+                date(year, JUN, 12) if year >= 2019 else date(year, MAY, 29),
+                "Democracy Day",
+            )
+
+        # Independence Day
+        collect_holiday(date(year, OCT, 1), "Independence Day")
+
+        # Christmas day
+        collect_holiday(date(year, DEC, 25), "Christmas Day")
+
+        # Boxing day
+        collect_holiday(date(year, DEC, 26), "Boxing Day")
 
         # Eid al-Fitr - Feast Festive
         # This is an estimate
         # date of observance is announced yearly
         for yr in (year - 1, year):
             for hol_date in _islamic_to_gre(yr, 10, 1):
-                _add_holiday(hol_date, "Eid al-Fitr")
-                _add_holiday(hol_date + td(days=+1), "Eid al-Fitr Holiday")
+                collect_holiday(hol_date, "Eid-el-Fitr")
+                collect_holiday(hol_date + td(days=+1), "Eid-el-Fitr Holiday")
 
-        # Arafat Day & Eid al-Adha - Scarfice Festive
+        # Eid al-Adha - Scarfice Festive
         # This is an estimate
         # date of observance is announced yearly
         for yr in (year - 1, year):
             for hol_date in _islamic_to_gre(yr, 12, 10):
-                _add_holiday(hol_date, "Eid al-Adha")
-                _add_holiday(hol_date + td(days=+1), "Eid al-Adha Holiday")
+                collect_holiday(hol_date, "Eid-el-Kabir")
+                collect_holiday(hol_date + td(days=+1), "Eid-el-Kabir Holiday")
 
         # Birthday of Prophet Muhammad
         for hol_date in _islamic_to_gre(year, 3, 12):
-            _add_holiday(hol_date, "Mawlid")
-
-        # Independence Day
-        self[date(year, OCT, 1)] = "Independence day"
-
-        # Christmas day
-        self[date(year, DEC, 25)] = "Christmas day"
-
-        # Boxing day
-        self[date(year, DEC, 26)] = "Boxing day"
-
-        # Democracy day moved around after its inception in 2000
-        # Initally it fell on May 29th
-        # In 2018 it was announced that the holiday
-        # will move to June 12th from 2019
-        if year >= 2019:
-            self[date(year, JUN, 12)] = "Democracy day"
-        elif year >= 2000:
-            self[date(year, MAY, 29)] = "Democracy day"
+            collect_holiday(hol_date, "Eid-el-Mawlid")
 
         # Observed holidays
         if self.observed and year >= 2016:
-            for k, v in list(self.items()):
-                if self._is_weekend(k) and k.year == year:
-                    next_workday = k + td(days=+1)
-                    while self._is_weekend(next_workday) or self.get(
-                        next_workday
+            hol_dates = list(holiday_date_names_mapping.keys())
+            for hol_date, hol_names in sorted(
+                holiday_date_names_mapping.items()
+            ):
+                if self._is_weekend(hol_date):
+                    next_workday = hol_date + td(days=+1)
+                    while (
+                        self._is_weekend(next_workday)
+                        or next_workday in hol_dates
                     ):
                         next_workday += td(days=+1)
-                    self[next_workday] = v + " (Observed)"
+                    for hol_name in hol_names:
+                        collect_holiday(next_workday, f"{hol_name} (Observed)")
+                    hol_dates.append(next_workday)
+
+        for hol_date, hol_names in holiday_date_names_mapping.items():
+            if hol_date.year == year:
+                for hol_name in hol_names:
+                    self[hol_date] = hol_name
 
 
 class NG(Nigeria):
diff --git a/holidays/countries/north_macedonia.py b/holidays/countries/north_macedonia.py
index feda3d682..380bd629e 100644
--- a/holidays/countries/north_macedonia.py
+++ b/holidays/countries/north_macedonia.py
@@ -14,9 +14,9 @@
 
 from dateutil.easter import EASTER_ORTHODOX, easter
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAY, SEP, AUG, OCT, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class NorthMacedonia(HolidayBase):
diff --git a/holidays/countries/pakistan.py b/holidays/countries/pakistan.py
index 93c35eb6c..10eb1cff1 100644
--- a/holidays/countries/pakistan.py
+++ b/holidays/countries/pakistan.py
@@ -13,10 +13,10 @@
 from datetime import timedelta as td
 from typing import Dict, Tuple, List
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
 from holidays.constants import OCT, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Pakistan(HolidayBase):
diff --git a/holidays/countries/peru.py b/holidays/countries/peru.py
index d8e1dbf0f..5fe46d76d 100644
--- a/holidays/countries/peru.py
+++ b/holidays/countries/peru.py
@@ -25,58 +25,58 @@ class Peru(HolidayBase):
     """
 
     country = "PE"
+    default_language = "es"
 
     def _populate(self, year):
         super()._populate(year)
 
         # New Year's Day
-        self[date(year, JAN, 1)] = "Año Nuevo [New Year's Day]"
+        self[date(year, JAN, 1)] = self.tr("Año Nuevo")
 
-        # Feast of Saints Peter and Paul
-        name = "San Pedro y San Pablo [Feast of Saints Peter and Paul]"
-        self[date(year, JUN, 29)] = name
+        easter_date = easter(year)
+        # Holy Thursday
+        self[easter_date + td(days=-3)] = self.tr("Jueves Santo")
 
-        # Independence Day
-        name = "Día de la Independencia [Independence Day]"
-        self[date(year, JUL, 28)] = name
+        # Good Friday
+        self[easter_date + td(days=-2)] = self.tr("Viernes Santo")
 
-        name = "Día de las Fuerzas Armadas y la Policía del Perú"
-        self[date(year, JUL, 29)] = name
+        # Easter Sunday
+        self[easter_date] = self.tr("Domingo de Resurrección")
 
-        # Santa Rosa de Lima
-        name = "Día de Santa Rosa de Lima"
-        self[date(year, AUG, 30)] = name
+        # Labor Day
+        self[date(year, MAY, 1)] = self.tr("Día del Trabajo")
 
-        # Battle of Angamos
-        name = "Combate Naval de Angamos [Battle of Angamos]"
-        self[date(year, OCT, 8)] = name
+        # Feast of Saints Peter and Paul
+        self[date(year, JUN, 29)] = self.tr("San Pedro y San Pablo")
 
-        easter_date = easter(year)
-        # Holy Thursday
-        self[easter_date + td(days=-3)] = "Jueves Santo [Maundy Thursday]"
+        # Independence Day
+        self[date(year, JUL, 28)] = self.tr("Día de la Independencia")
 
-        # Good Friday
-        self[easter_date + td(days=-2)] = "Viernes Santo [Good Friday]"
+        # Great Military Parade Day
+        self[date(year, JUL, 29)] = self.tr("Día de la Gran Parada Militar")
 
-        # Holy Saturday
-        self[easter_date + td(days=-1)] = "Sábado de Gloria [Holy Saturday]"
+        if year >= 2022:
+            # Battle of Junín
+            self[date(year, AUG, 6)] = self.tr("Batalla de Junín")
 
-        # Easter Sunday
-        self[easter_date] = "Domingo de Resurrección [Easter Sunday]"
+        # Santa Rosa de Lima
+        self[date(year, AUG, 30)] = self.tr("Santa Rosa de Lima")
 
-        # Labor Day
-        self[date(year, MAY, 1)] = "Día del Trabajo [Labour Day]"
+        # Battle of Angamos
+        self[date(year, OCT, 8)] = self.tr("Combate de Angamos")
 
         # All Saints Day
-        name = "Día de Todos Los Santos [All Saints Day]"
-        self[date(year, NOV, 1)] = name
+        self[date(year, NOV, 1)] = self.tr("Todos Los Santos")
+
+        # Immaculate Conception
+        self[date(year, DEC, 8)] = self.tr("Inmaculada Concepción")
 
-        # Inmaculada Concepción
-        name = "Inmaculada Concepción [Immaculate Conception]"
-        self[date(year, DEC, 8)] = name
+        if year >= 2022:
+            # Battle of Ayacucho
+            self[date(year, DEC, 9)] = self.tr("Batalla de Ayacucho")
 
         # Christmas
-        self[date(year, DEC, 25)] = "Navidad [Christmas]"
+        self[date(year, DEC, 25)] = self.tr("Navidad del Señor")
 
 
 class PE(Peru):
diff --git a/holidays/countries/philippines.py b/holidays/countries/philippines.py
index e48cf03cd..eb65a0f12 100644
--- a/holidays/countries/philippines.py
+++ b/holidays/countries/philippines.py
@@ -13,12 +13,11 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, FEB, APR, MAY, JUN, AUG, NOV, DEC
+from holidays.calendars import _ChineseLuniSolar, _islamic_to_gre
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, FEB, APR, MAY, JUN, AUG, NOV, DEC, MON
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _ChineseLuniSolar, _islamic_to_gre
 
 
 class Philippines(HolidayBase):
@@ -76,7 +75,9 @@ def _populate(self, year):
         self[date(year, AUG, 21)] = "Ninoy Aquino Day"
 
         # National Heroes Day.
-        self[date(year, AUG, 31) + rd(weekday=MO(-1))] = "National Heroes Day"
+        self[
+            _get_nth_weekday_of_month(-1, MON, AUG, year)
+        ] = "National Heroes Day"
 
         # All Saints' Day.
         self[date(year, NOV, 1)] = "All Saints' Day"
diff --git a/holidays/countries/saudi_arabia.py b/holidays/countries/saudi_arabia.py
index b24319683..270c96e4a 100644
--- a/holidays/countries/saudi_arabia.py
+++ b/holidays/countries/saudi_arabia.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
-from holidays.constants import FEB, SEP, THU, FRI, SAT
+from holidays.calendars import _islamic_to_gre
+from holidays.constants import FEB, SEP, NOV, THU, FRI, SAT
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class SaudiArabia(HolidayBase):
@@ -28,25 +28,40 @@ class SaudiArabia(HolidayBase):
     Islamic Calendar, and they are estimates as they announced each
     year and based on moon sightings;
     they are:
-        - Eid al-Fitr*
-        - Eid al-Adha*
-    * only if hijri-converter library is installed, otherwise a warning is
-    raised that this holiday is missing. hijri-converter requires
-    Python >= 3.6
+        - Eid al-Fitr
+        - Eid al-Adha
     """
 
     country = "SA"
+    special_holidays = {
+        # celebrate the country's win against Argentina in the World Cup
+        2022: ((NOV, 23, "National Holiday"),),
+    }
 
     def _populate(self, year):
-        super()._populate(year)
-
-        # Weekend used to be THU, FRI before June 28th, 2013.
-        # On that year both Eids were after that date, and founding
-        # day holiday started at 2022; so what below works.
-        # It has to be a tuple (subscriptable) due to a business logic below.
-        self.weekend = (THU, FRI) if year < 2013 else (FRI, SAT)
-
-        observed_str = " (observed)"
+        def _add_with_observed(hol_date: date, hol_name: str) -> None:
+            if hol_date in self:
+                return None
+            self[hol_date] = hol_name
+            if self.observed:
+                weekend = (THU, FRI) if year <= 2012 else (FRI, SAT)
+                # 1st weekend day (Thursday before 2013 and Friday otherwise)
+                if hol_date.weekday() == weekend[0]:
+                    self[hol_date + td(days=-1)] = f"{hol_name}{observed_str}"
+                # 2nd weekend day (Friday before 2013 and Saturday otherwise)
+                elif hol_date.weekday() == weekend[1]:
+                    self[hol_date + td(days=+1)] = f"{hol_name}{observed_str}"
+
+        def _add_islamic_observed(hol_date: date, hol_name: str) -> None:
+            if self.observed:
+                weekend_days = sum(
+                    self._is_weekend(hol_date + td(days=i)) for i in range(4)
+                )
+                for i in range(weekend_days):
+                    _add_holiday(
+                        hol_date + td(days=+4 + i),
+                        f"{hol_name}{observed_str}",
+                    )
 
         def _add_holiday(dt: date, hol: str) -> None:
             """Only add if in current year; prevents adding holidays across
@@ -56,6 +71,15 @@ def _add_holiday(dt: date, hol: str) -> None:
             if dt.year == year:
                 self[dt] = hol
 
+        super()._populate(year)
+
+        # Weekend used to be THU, FRI before June 28th, 2013.
+        # On that year both Eids were after that date, and Founding day
+        # holiday started at 2022; so what below works.
+        self.weekend = {THU, FRI} if year <= 2012 else {FRI, SAT}
+
+        observed_str = " (observed)"
+
         # Eid al-Fitr Holiday
         # The holiday is a 4-day holiday starting on the day following the
         # 29th day of Ramadan, the 9th month of the Islamic calendar.
@@ -65,20 +89,10 @@ def _add_holiday(dt: date, hol: str) -> None:
         # Date of observance is announced yearly.
         holiday_name = "Eid al-Fitr Holiday"
         for yr in (year - 1, year):
-            for hijri_date in _islamic_to_gre(yr, 9, 29):
-                hijri_date += td(days=+1)
+            for hijri_date in _islamic_to_gre(yr, 10, 1):
                 for dys in range(4):
-                    _add_holiday((hijri_date + td(days=dys)), holiday_name)
-                if self.observed:
-                    weekend_days = sum(
-                        (hijri_date + td(days=dys)).weekday() in self.weekend
-                        for dys in range(4)
-                    )
-                    for dys in range(weekend_days):
-                        _add_holiday(
-                            hijri_date + td(days=4 + dys),
-                            holiday_name + observed_str,
-                        )
+                    _add_holiday(hijri_date + td(days=dys), holiday_name)
+                _add_islamic_observed(hijri_date, holiday_name)
 
         # Arafat Day & Eid al-Adha
         # The holiday is a 4-day holiday starting on Arafat Day, the 10th of
@@ -92,55 +106,20 @@ def _add_holiday(dt: date, hol: str) -> None:
             for hijri_date in _islamic_to_gre(yr, 12, 9):
                 _add_holiday(hijri_date, "Arafat Day Holiday")
                 for dys in range(1, 4):
-                    _add_holiday((hijri_date + td(days=dys)), holiday_name)
-                if self.observed:
-                    weekend_days = sum(
-                        (hijri_date + td(days=dys)).weekday() in self.weekend
-                        for dys in range(4)
-                    )
-                    for dys in range(weekend_days):
-                        _add_holiday(
-                            hijri_date + td(days=4 + dys),
-                            holiday_name + observed_str,
-                        )
+                    _add_holiday(hijri_date + td(days=dys), holiday_name)
+                _add_islamic_observed(hijri_date, holiday_name)
 
         # National Day holiday (started at the year 2005).
         # Note: if national day happens within the Eid al-Fitr Holiday or
         # within Eid al-Fitr Holiday, there is no extra holidays given for it.
-        holiday_name = "National Day Holiday"
         if year >= 2005:
-            national_day = date(year, SEP, 23)
-            if national_day not in self:
-                self[national_day] = holiday_name
-                # First weekend day(Thursaday before 2013 and Friday otherwise)
-                if self.observed and national_day.weekday() == self.weekend[0]:
-                    national_day += td(days=-1)
-                    self[national_day] = holiday_name + observed_str
-                # Second weekend day(Friday before 2013 and Saturday otherwise)
-                elif (
-                    self.observed and national_day.weekday() == self.weekend[1]
-                ):
-                    national_day += td(days=+1)
-                    self[national_day] = holiday_name + observed_str
+            _add_with_observed(date(year, SEP, 23), "National Day Holiday")
 
         # Founding Day holiday (started 2022).
         # Note: if founding day happens within the Eid al-Fitr Holiday or
         # within Eid al-Fitr Holiday, there is no extra holidays given for it.
-        holiday_name = "Founding Day Holiday"
         if year >= 2022:
-            founding_day = date(year, FEB, 22)
-            if founding_day not in self:
-                self[founding_day] = holiday_name
-                # First weekend day(Thursaday before 2013 and Friday otherwise)
-                if self.observed and founding_day.weekday() == self.weekend[0]:
-                    founding_day += td(days=-1)
-                    self[founding_day] = holiday_name + observed_str
-                # Second weekend day(Friday before 2013 and Saturday otherwise)
-                elif (
-                    self.observed and founding_day.weekday() == self.weekend[1]
-                ):
-                    founding_day += td(days=+1)
-                    self[founding_day] = holiday_name + observed_str
+            _add_with_observed(date(year, FEB, 22), "Founding Day Holiday")
 
 
 class SA(SaudiArabia):
diff --git a/holidays/countries/singapore.py b/holidays/countries/singapore.py
index e8c6a9809..1c782f26d 100644
--- a/holidays/countries/singapore.py
+++ b/holidays/countries/singapore.py
@@ -15,10 +15,10 @@
 
 from dateutil.easter import easter
 
+from holidays.calendars import _ChineseLuniSolar, _islamic_to_gre
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
 from holidays.constants import OCT, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _ChineseLuniSolar, _islamic_to_gre
 
 
 class Singapore(HolidayBase):
diff --git a/holidays/countries/south_africa.py b/holidays/countries/south_africa.py
index e5740e7e1..1d40c64e3 100644
--- a/holidays/countries/south_africa.py
+++ b/holidays/countries/south_africa.py
@@ -13,11 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO, FR
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _get_nth_weekday_of_month
 from holidays.constants import JAN, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT
-from holidays.constants import NOV, DEC
+from holidays.constants import NOV, DEC, MON, FRI
 from holidays.holiday_base import HolidayBase
 
 
@@ -112,7 +111,7 @@ def _add_with_observed(hol_date: date, hol_name: str) -> None:
 
         if 1987 <= year <= 1989:
             # observed on first Friday in May
-            self[date(year, MAY, 1) + rd(weekday=FR)] = "Workers' Day"
+            self[_get_nth_weekday_of_month(1, FRI, MAY, year)] = "Workers' Day"
 
         if year <= 1993:
             self[easter_date + td(days=+40)] = "Ascension Day"
@@ -127,18 +126,24 @@ def _add_with_observed(hol_date: date, hol_name: str) -> None:
 
         if 1952 <= year <= 1960:
             # observed on second Monday in July
-            self[date(year, JUL, 1) + rd(weekday=MO(+2))] = "Queen's Birthday"
+            self[
+                _get_nth_weekday_of_month(2, MON, JUL, year)
+            ] = "Queen's Birthday"
 
         if 1961 <= year <= 1973:
             self[date(year, JUL, 10)] = "Family Day"
 
         if year <= 1951:
             # observed on first Monday in August
-            self[date(year, AUG, 1) + rd(weekday=MO)] = "King's Birthday"
+            self[
+                _get_nth_weekday_of_month(1, MON, AUG, year)
+            ] = "King's Birthday"
 
         if 1952 <= year <= 1979:
             # observed on first Monday in September
-            self[date(year, SEP, 1) + rd(weekday=MO)] = "Settlers' Day"
+            self[
+                _get_nth_weekday_of_month(1, MON, SEP, year)
+            ] = "Settlers' Day"
 
         if 1952 <= year <= 1993:
             self[date(year, OCT, 10)] = "Kruger Day"
diff --git a/holidays/countries/spain.py b/holidays/countries/spain.py
index 5ab318ae5..3fbe45209 100644
--- a/holidays/countries/spain.py
+++ b/holidays/countries/spain.py
@@ -14,10 +14,10 @@
 
 from dateutil.easter import easter
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
 from holidays.constants import OCT, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Spain(HolidayBase):
diff --git a/holidays/countries/sweden.py b/holidays/countries/sweden.py
index e7fc8d52d..d625d283d 100644
--- a/holidays/countries/sweden.py
+++ b/holidays/countries/sweden.py
@@ -14,10 +14,10 @@
 
 from dateutil import rrule
 from dateutil.easter import easter
-from dateutil.relativedelta import FR, SA, SU
-from dateutil.relativedelta import relativedelta as rd
+from dateutil.relativedelta import SU
 
-from holidays.constants import JAN, MAR, MAY, JUN, OCT, DEC
+from holidays.calendars import _get_nth_weekday_from
+from holidays.constants import JAN, MAR, MAY, JUN, OCT, DEC, FRI, SAT
 from holidays.holiday_base import HolidayBase
 
 
@@ -93,15 +93,18 @@ def _populate(self, year):
         # https://www.nordiskamuseet.se/aretsdagar/midsommarafton
         if year >= 1953:
             # Midsummer evening. Friday between June 19th and June 25th
-            self[date(year, JUN, 19) + rd(weekday=FR)] = "Midsommarafton"
+            dt = _get_nth_weekday_from(1, FRI, date(year, JUN, 19))
+            self[dt] = "Midsommarafton"
             # Midsummer day. Saturday between June 20th and June 26th
-            self[date(year, JUN, 20) + rd(weekday=SA)] = "Midsommardagen"
+            self[dt + td(days=+1)] = "Midsommardagen"
         else:
             self[date(year, JUN, 23)] = "Midsommarafton"
             self[date(year, JUN, 24)] = "Midsommardagen"
 
         # All saints day. Saturday between October 31th and November 6th
-        self[date(year, OCT, 31) + rd(weekday=SA)] = "Alla helgons dag"
+        self[
+            _get_nth_weekday_from(1, SAT, date(year, OCT, 31))
+        ] = "Alla helgons dag"
 
         if year <= 1953:
             self[date(year, MAR, 25)] = "Jungfru Marie bebådelsedag"
diff --git a/holidays/countries/switzerland.py b/holidays/countries/switzerland.py
index f54147387..d73aa1539 100644
--- a/holidays/countries/switzerland.py
+++ b/holidays/countries/switzerland.py
@@ -13,10 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import TH, SU
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _get_nth_weekday_of_month
 from holidays.constants import JAN, MAR, APR, MAY, JUN, AUG, SEP, NOV, DEC
+from holidays.constants import THU, SUN
 from holidays.holiday_base import HolidayBase
 
 
@@ -88,7 +88,7 @@ def _populate(self, year):
         easter_date = easter(year)
         # Näfelser Fahrt (first Thursday in April but not in Holy Week)
         if self.subdiv == "GL" and year >= 1835:
-            dt = date(year, APR, 1) + rd(weekday=TH)
+            dt = _get_nth_weekday_of_month(1, THU, APR, year)
             if dt == easter_date + td(days=-3):
                 dt += td(days=+7)
             self[dt] = "Näfelser Fahrt"
@@ -160,12 +160,12 @@ def _populate(self, year):
 
         if self.subdiv == "VD":
             # Monday after the third Sunday of September
-            dt = date(year, SEP, 1) + rd(weekday=SU(+3)) + td(days=+1)
+            dt = _get_nth_weekday_of_month(3, SUN, SEP, year) + td(days=+1)
             self[dt] = "Lundi du Jeûne"
 
         if self.subdiv == "GE":
             # Thursday after the first Sunday of September
-            dt = date(year, SEP, 1) + rd(weekday=SU) + td(days=+4)
+            dt = _get_nth_weekday_of_month(1, SUN, SEP, year) + td(days=+4)
             self[dt] = "Jeûne genevois"
 
         if self.subdiv == "OW":
diff --git a/holidays/countries/taiwan.py b/holidays/countries/taiwan.py
index c910ff3ad..a7f191849 100644
--- a/holidays/countries/taiwan.py
+++ b/holidays/countries/taiwan.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _ChineseLuniSolar
 from holidays.constants import JAN, FEB, APR, OCT
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _ChineseLuniSolar
 
 
 class Taiwan(HolidayBase):
diff --git a/holidays/countries/thailand.py b/holidays/countries/thailand.py
index dec4220a2..d4e138a18 100644
--- a/holidays/countries/thailand.py
+++ b/holidays/countries/thailand.py
@@ -11,11 +11,12 @@
 
 from datetime import date
 from datetime import timedelta as td
+from gettext import gettext as tr
 
+from holidays.calendars import _ThaiLuniSolar
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
 from holidays.constants import OCT, NOV, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _ThaiLuniSolar
 
 
 class Thailand(HolidayBase):
@@ -57,7 +58,7 @@ class Thailand(HolidayBase):
         https://www.brh.go.th/index.php/2019-02-27-04-11-52/542-12-2564
     - [HM King Bhumibol Adulyadej Memorial Day]
         https://www.matichon.co.th/politics/news_526200
-    - [Chulalongkorn Memorial Day]
+    - [HM King Chulalongkorn Memorial Day]
         https://th.wikipedia.org/wiki/วันปิยมหาราช
     - [HM King Bhumibol Adulyadej's Birthday]
         (Ministry of Culture 's wbm) http://tiny.cc/wa_mincul_nat_day
@@ -111,36 +112,40 @@ class Thailand(HolidayBase):
     """
 
     country = "TH"
+    default_language = "th"
 
-    # วันหยุดพิเศษ (เพิ่มเติม) - see Bank of Thailand's DB for Cross-Check
-    thai_special_in_lieu_holidays = "Special In Lieu Holiday"
-    thai_election = "Thai Election Day"
-    thai_election_in_lieu = "Thai Election Day (in lieu)"
-    thai_bridge_public_holiday = "Bridge Public Holiday"
+    # วันหยุดพิเศษ (เพิ่มเติม) - see Bank of Thailand's DB for Cross-Check.
 
-    # Special Cases
-    rama_ix_golden_jubilee = "HM King Bhumibol Adulyadej's Golden Jubilee"
-    rama_ix_sixty_accession = (
-        "HM King Bhumibol Adulyadej's 60th Anniversary of Accession Event"
+    thai_special_in_lieu_holidays = tr("วันหยุดชดเชย")
+    thai_election = tr("วันเลือกตั้ง")
+    thai_election_in_lieu = tr("ชดเชย%s") % thai_election
+    thai_bridge_public_holiday = tr("วันหยุดพิเศษ (เพิ่มเติม)")
+
+    # Special Cases.
+
+    rama_ix_golden_jubilee = tr("พระราชพิธีกาญจนาภิเษก พ.ศ. 2539")
+    rama_ix_sixty_accession = tr(
+        "พระราชพิธีฉลองสิริราชสมบัติครบ 60 ปี พ.ศ. 2549"
     )
-    thai_military_emergency_lockdown = (
-        "Emergency Lockdown (Thai Military Coup d'état)"
+    thai_military_emergency_lockdown = tr("วันหยุดพิเศษ (คมช.)")
+    thai_political_emergency_lockdown = tr("วันหยุดพิเศษ (การเมือง)")
+    thai_flood_2011_emergency_lockdown = tr(
+        "วันหยุดพิเศษ (มหาอุทกภัย พ.ศ. 2554)"
     )
-    thai_political_emergency_lockdown = (
-        "Emergency Lockdown (Thai Political Unrest)"
+    rama_ix_mourning = tr(
+        "วันหยุดพิเศษ (ร่วมถวายอาลัย ส่งดวงพระวิญญาณพระบรมศพ)"
     )
-    thai_flood_2011_emergency_lockdown = (
-        "Emergency Lockdown (2011 Thailand Floods)"
+    rama_ix_cremation = tr(
+        "วันพระราชพิธีถวายพระเพลิงพระบรมศพ"
+        "พระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช"
     )
-    rama_ix_mourning = "Day of Mourning for HM King Bhumibol Adulyadej"
-    rama_ix_cremation = "HM King Bhumibol Adulyadej's Royal Cremation Ceremony"
-    rama_x_coronation_celebrations = (
-        "HM King Maha Vajiralongkorn's Coronation Celebrations"
+    rama_x_coronation_celebrations = tr(
+        "พระราชพิธีบรมราชาภิเษก พระบาทสมเด็จพระวชิรเกล้าเจ้าอยู่หัว"
     )
-    songkran_festival_in_lieu_covid = "Songkran Festival (in lieu)"
+    songkran_festival_in_lieu_covid = tr("ชดเชย%s") % tr("วันสงกรานต์")
 
     special_holidays = {
-        # 1992-1994 (include In Lieus, Checked with Bank of Thailand Data)
+        # 1992-1994 (include In Lieus, Checked with Bank of Thailand Data).
         1992: (
             (MAY, 18, thai_special_in_lieu_holidays),
             (DEC, 7, thai_special_in_lieu_holidays),
@@ -158,9 +163,9 @@ class Thailand(HolidayBase):
             (OCT, 24, thai_special_in_lieu_holidays),
             (DEC, 12, thai_special_in_lieu_holidays),
         ),
-        # 1995-1997 (Bank of Thailand Data)
+        # 1995-1997 (Bank of Thailand Data).
         1996: ((JUN, 10, rama_ix_golden_jubilee),),
-        # 1998-2000 (include In Lieus, Checked with Bank of Thailand Data)
+        # 1998-2000 (include In Lieus, Checked with Bank of Thailand Data).
         1998: (
             (MAY, 11, thai_special_in_lieu_holidays),
             (DEC, 7, thai_special_in_lieu_holidays),
@@ -178,7 +183,7 @@ class Thailand(HolidayBase):
             (DEC, 11, thai_special_in_lieu_holidays),
             (DEC, 29, thai_election),
         ),
-        # From 2001 Onwards (Checked with Bank of Thailand Data)
+        # From 2001 Onwards (Checked with Bank of Thailand Data).
         2006: (
             (APR, 19, thai_election),
             (JUN, 9, rama_ix_sixty_accession),
@@ -203,6 +208,8 @@ class Thailand(HolidayBase):
             (MAY, 16, thai_bridge_public_holiday),
             (OCT, 27, thai_flood_2011_emergency_lockdown),
             (OCT, 28, thai_flood_2011_emergency_lockdown),
+            (OCT, 29, thai_flood_2011_emergency_lockdown),
+            (OCT, 30, thai_flood_2011_emergency_lockdown),
             (OCT, 31, thai_flood_2011_emergency_lockdown),
         ),
         2012: ((APR, 9, thai_bridge_public_holiday),),
@@ -246,8 +253,8 @@ def __init__(self, **kwargs) -> None:
         super().__init__(**kwargs)
 
     def _populate(self, year):
-        # Due to Thai Calendar Migration, this is capped off at 1941
-        # But certain holidays were implemented before 1941
+        # Due to Thai Calendar Migration, this is capped off at 1941.
+        # But certain holidays were implemented before 1941.
         if year <= 1940:
             return None
 
@@ -276,33 +283,30 @@ def _add_with_observed(dt, holiday_name) -> None:
             if 1961 <= year <= 1973 or 1995 <= year <= 1997 or year >= 2001:
                 if self.observed and self._is_weekend(dt):
                     in_lieu = dt + td(days=+2 if self._is_saturday(dt) else +1)
-                    self[in_lieu] = f"{holiday_name} (in lieu)"
+                    self[in_lieu] = self.tr("ชดเชย%s") % holiday_name
 
         super()._populate(year)
 
-        ########################
-        #
-        # FIXED DATED HOLIDAYS
-        #
-        ########################
+        # Fixed Date Holidays
 
-        # !!! New Year's Day !!!
+        # New Year's Day.
         # วันขึ้นปีใหม่
-        # Status: In-Use
-        # Starts in the present form in 1941 (B.E. 2484)
+        # Status: In-Use.
+        # Starts in the present form in 1941 (B.E. 2484).
         # TODO: Add check for 1941 if we support earlier dates.
 
-        _add_with_observed(date(year, JAN, 1), "New Year's Day")
+        _add_with_observed(date(year, JAN, 1), self.tr("วันขึ้นปีใหม่"))
 
-        # !!! New Year's Eve (in lieu) !!!
+        # New Year's Eve (in lieu).
         # วันหยุดชดเชยวันสิ้นปี
-        # Status: In-Use
+        # Status: In-Use.
         # Added separately from New Year's Eve itself so that it would't
-        #   go over the next year
-        #   - CASE 1: SAT-SUN -> 1 in-lieu on TUE
-        #   - CASE 2: SUN-MON -> 1 in-lieu on TUE
-        # See in lieu logic in `_add_with_observed(dt, holiday_name)`
-        new_years_eve_in_lieu = "New Year's Eve (in lieu)"
+        #   go over the next year.
+        #   - CASE 1: SAT-SUN -> 1 in-lieu on TUE.
+        #   - CASE 2: SUN-MON -> 1 in-lieu on TUE.
+        # See in lieu logic in `_add_with_observed(dt, holiday_name)`.
+
+        new_years_eve_in_lieu = self.tr("ชดเชย%s") % self.tr("วันสิ้นปี")
 
         if self.observed and (1995 <= year <= 1997 or year >= 2001):
             if self._is_saturday(date(year - 1, DEC, 31)):
@@ -310,28 +314,29 @@ def _add_with_observed(dt, holiday_name) -> None:
             elif self._is_sunday(date(year - 1, DEC, 31)):
                 self[date(year, JAN, 2)] = new_years_eve_in_lieu
 
-        # !!! Chakri Memorial Day !!!
+        # Chakri Memorial Day.
         # วันจักรี
-        # Status: In-Use
-        # Starts in present form in 1918 (B.E. 2461)
+        # Status: In-Use.
+        # Starts in present form in 1918 (B.E. 2461).
         # TODO: Add check for 1918 if we support earlier dates.
 
-        _add_with_observed(date(year, APR, 6), "Chakri Memorial Day")
+        _add_with_observed(date(year, APR, 6), self.tr("วันจักรี"))
 
-        # !!! Songkran Festival !!!
+        # Songkran Festival.
         # วันสงกรานต์
-        # Status: In-Use
-        # Used to be April 1st as Thai New Year Day
+        # Status: In-Use.
+        # Used to be April 1st as Thai New Year Day.
         # Initially abandoned in 1941 (B.E. 2484), declared again as
-        #   public holidays in 1948 (2491 B.E)
+        #   public holidays in 1948 (2491 B.E).
         #  - 1948-1953, celebrated on Apr 13-15
         #  - 1954-1956, abandoned as a public holiday
         #  - 1957-1988, only celebrated on Apr 13
         #  - 1989-1997, celebrated on Apr 12-14
         #  - 1998-Present, celebrated on Apr 13-15
         #    (Except for 2020 due to Covid-19 outbreaks)
-        # This has its own in-lieu trigger
-        songkran_festival = "Songkran Festival"
+        # This has its own in-lieu trigger.
+
+        songkran_festival = self.tr("วันสงกรานต์")
 
         if 1948 <= year <= 1953:
             self[date(year, APR, 13)] = songkran_festival
@@ -348,17 +353,17 @@ def _add_with_observed(dt, holiday_name) -> None:
             self[date(year, APR, 14)] = songkran_festival
             self[date(year, APR, 15)] = songkran_festival
 
-        # !!! Songkran Festival (in lieu) !!!
+        # Songkran Festival (in lieu).
         # วันหยุดชดเชยวันสงกรานต์
         # If Songkran happened to be held on the weekends, only one in-lieu
-        #   public holiday is added, No in lieus for SUN-MON-TUE case
+        #   public holiday is added, No in lieus for SUN-MON-TUE case.
         #   - CASE 1: THU-FRI-SAT -> 1 in-lieu on MON
         #   - CASE 2: FRI-SAT-SUN -> 1 in-lieu on MON
         #   - CASE 3: SAT-SUN-MON -> 1 in-lieu on TUE
-        # See in lieu logic in `_add_with_observed(dt, holiday_name)`
-        # Status: In Use
+        # See in lieu logic in `_add_with_observed(dt, holiday_name)`.
+        # Status: In Use.
 
-        songkran_festival_in_lieu = "Songkran Festival (in lieu)"
+        songkran_festival_in_lieu = self.tr("ชดเชย%s") % songkran_festival
 
         if self.observed and (1995 <= year <= 1997 or year >= 2001):
             dt = date(year, APR, 15) if year >= 2001 else date(year, APR, 14)
@@ -370,155 +375,204 @@ def _add_with_observed(dt, holiday_name) -> None:
             elif self._is_monday(dt):
                 self[dt + td(days=+1)] = songkran_festival_in_lieu
 
-        # !!! National Labour day !!!
+        # National Labour day.
         # วันแรงงานแห่งชาติ
-        # Status: In-Use
-        # Starts in the present form in 1974 (B.E. 2517)
+        # Status: In-Use.
+        # Starts in the present form in 1974 (B.E. 2517).
         # Does existed officially since 1956 (B.E. 2499),
-        #   but wasn't a public holiday until then
-        # *** NOTE: only observed by financial and private sectors
+        #   but wasn't a public holiday until then.
+        # *** NOTE: only observed by financial and private sectors.
 
         if year >= 1974:
-            _add_with_observed(date(year, MAY, 1), "National Labour Day")
+            _add_with_observed(
+                date(year, MAY, 1), self.tr("วันแรงงานแห่งชาติ")
+            )
 
-        # !!! National Day (24 June) !!!
+        # National Day (24 June).
         # วันชาติ
-        # Status: Defunct (Historical)
-        # Starts in 1939 (B.E. 2482) by Plaek Phibunsongkhram
-        # Replaced by Rama IX's birthday in 1960 (B.E. 2503) by Sarit Thanarat
+        # Status: Defunct (Historical).
+        # Starts in 1939 (B.E. 2482) by Plaek Phibunsongkhram.
+        # Replaced by Rama IX's birthday in 1960 (B.E. 2503) by Sarit Thanarat.
         # TODO: Add check for 1939 if we support earlier dates.
 
-        if year <= 1959:
-            _add_with_observed(date(year, JUN, 24), "National Day")
+        _add_with_observed(
+            date(year, JUN, 24) if year <= 1959 else date(year, DEC, 5),
+            self.tr("วันชาติ"),
+        )
 
-        # !!! Coronation Day !!!
+        # Coronation Day.
         # วันฉัตรมงคล
-        # Starts in 1958 (B.E. 2501) for Rama IX's Coronation: May 5th
-        # No celebration in 2017-2019 (B.E 2560-2562)
-        # Reestablished with Rama X's Coronation in 2020: May 4th
-        coronation_day = "Coronation Day"
+        # Starts in 1958 (B.E. 2501) for Rama IX's Coronation: May 5th.
+        # No celebration in 2017-2019 (B.E 2560-2562).
+        # Reestablished with Rama X's Coronation in 2020: May 4th.
+
+        coronation_day = self.tr("วันฉัตรมงคล")
 
         if 1958 <= year <= 2016:
             _add_with_observed(date(year, MAY, 5), coronation_day)
         elif year >= 2020:
             _add_with_observed(date(year, MAY, 4), coronation_day)
 
-        # !!! HM Queen Suthida's Birthday !!!
+        # HM Queen Suthida's Birthday.
         # วันเฉลิมพระชนมพรรษา พระราชินี
-        # Status: In-Use
-        # Starts in 2019 (B.E. 2562)
+        # Status: In-Use.
+        # Starts in 2019 (B.E. 2562).
 
         if year >= 2019:
             _add_with_observed(
-                date(year, JUN, 3), "HM Queen Suthida's Birthday"
+                date(year, JUN, 3),
+                self.tr(
+                    "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสุทิดา "
+                    "พัชรสุธาพิมลลักษณ พระบรมราชินี"
+                ),
             )
 
-        # !!! HM King Maha Vajiralongkorn's Birthday !!!
+        # HM King Maha Vajiralongkorn's Birthday.
         # วันเฉลิมพระชนมพรรษา รัชกาลที่ 10
-        # Status: In-Use
-        # Started in 2017 (B.E 2560)
+        # Status: In-Use.
+        # Started in 2017 (B.E 2560).
 
         if year >= 2017:
             _add_with_observed(
-                date(year, JUL, 28), "HM King Maha Vajiralongkorn's Birthday"
+                date(year, JUL, 28),
+                self.tr(
+                    "วันเฉลิมพระชนมพรรษา"
+                    "พระบาทสมเด็จพระปรเมนทรรามาธิบดีศรีสินทรมหาวชิราลงกรณ "
+                    "พระวชิรเกล้าเจ้าอยู่หัว"
+                ),
             )
 
-        # !!! HM Queen Sirikit the Queen Mother's Birthday !!!
-        # วันเฉลิมพระชนมพรรษา พระบรมราชินีนาถ ( 1976-2017),
+        # HM Queen Sirikit the Queen Mother's Birthday.
+        # วันเฉลิมพระชนมพรรษา พระบรมราชินีนาถ ( 1976-2017)
         # วันเฉลิมพระชนมพรรษา พระบรมราชชนนีพันปีหลวง (2017-Present)
-        # Status: In-Use
-        # Started in 1976 (B.E. 2519) alongside Mother's Day
-        # Initial celebration as HM Queen Sirikit's Birthday
+        # Status: In-Use.
+        # Started in 1976 (B.E. 2519) alongside Mother's Day.
+        # Initial celebration as HM Queen Sirikit's Birthday.
         # Now acts as the Queen Mother from 2017 onwards.
 
         if 1976 <= year <= 2016:
             _add_with_observed(
-                date(year, AUG, 12), "HM Queen Sirikit's Birthday"
+                date(year, AUG, 12),
+                self.tr(
+                    "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสิริกิติ์ "
+                    "พระบรมราชินีนาถ"
+                ),
             )
         elif year >= 2017:
             _add_with_observed(
                 date(year, AUG, 12),
-                "HM Queen Sirikit The Queen Mother's Birthday",
+                self.tr("วันเฉลิมพระชนมพรรษาสมเด็จพระบรมราชชนนีพันปีหลวง"),
             )
 
-        # !!! National Mother's Day !!!
+        # National Mother's Day.
         # วันแม่แห่งชาติ
-        # Status: In-Use
+        # Status: In-Use.
         # Started 1950 (B.E 2493) initially as April 15 and cancelled in
         #   1958 (B.E 2501) when the Min. of Culture was abolished.
         # Restarts again in 1976 (B.E. 2519) on Queen Sirikit's Birthday
         #   (August 12) and stay that way from that point onwards.
-        thai_mothers_day = "National Mother's Day"
+
+        thai_mothers_day = self.tr("วันแม่แห่งชาติ")
 
         if 1950 <= year <= 1957:
             _add_with_observed(date(year, APR, 15), thai_mothers_day)
         elif year >= 1976:
             _add_with_observed(date(year, AUG, 12), thai_mothers_day)
 
-        # !!! Anniversary for the Death of King Bhumibol Adulyadej !!!
+        # Anniversary for the Death of King Bhumibol Adulyadej.
         # วันคล้ายวันสวรรคตพระบาทสมเด็จพระปรมินทร มหาภูมิพลอดุลยเดช บรมนาถบพิตร
-        # Status: In-Use
-        # Started in 2017 (B.E 2560)
+        # Status: In-Use.
+        # Started in 2017 (B.E 2560).
+        # Got conferred with 'the Great' title in 2019 (B.E. 2562).
 
-        if year >= 2017:
+        if 2017 <= year <= 2018:
+            _add_with_observed(
+                date(year, OCT, 13),
+                self.tr(
+                    "วันคล้ายวันสวรรคตพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช "
+                    "บรมนาถบพิตร"
+                ),
+            )
+        elif year >= 2019:
             _add_with_observed(
-                date(year, OCT, 13), "HM King Bhumibol Adulyadej Memorial Day"
+                date(year, OCT, 13),
+                self.tr(
+                    "วันคล้ายวันสวรรคตพระบาทสมเด็จพระบรมชนกาธิเบศร "
+                    "มหาภูมิพลอดุลยเดชมหาราช บรมนาถบพิตร"
+                ),
             )
 
-        # !!! Chulalongkorn Memorial Day !!!
+        # HM King Chulalongkorn Memorial Day.
         # วันปิยมหาราช
-        # Status: In-Use
-        # Started in 1911 (B.E. 2454)
+        # Status: In-Use.
+        # Started in 1911 (B.E. 2454).
         # TODO: Add check for 1911 if we support earlier dates.
 
-        _add_with_observed(date(year, OCT, 23), "Chulalongkorn Memorial Day")
+        _add_with_observed(date(year, OCT, 23), self.tr("วันปิยมหาราช"))
 
-        # !!! HM King Bhumibol Adulyadej's Birthday Anniversary !!!
-        # วันเฉลิมพระชนมพรรษา รัชกาลที่ 9 (1960-2016),
-        # วันคล้ายยวันเฉลิมพระชนมพรรษา รัชกาลที่ 9 (2017-Present)
-        # Status: In-Use
-        # Replaced Nataion Day (26 June) in 1960 (B.E. 2503) by Sarit Thanarat
-        # Confirmed as still in-use in 2017
+        # HM King Bhumibol Adulyadej's Birthday Anniversary.
+        # วันเฉลิมพระชนมพรรษา รัชกาลที่ 9 (1960-2016)
+        # วันคล้ายวันเฉลิมพระชนมพรรษา รัชกาลที่ 9 (2017-Present)
+        # Status: In-Use.
+        # Replaced Nataion Day (26 June) in 1960 (B.E. 2503) by Sarit Thanarat.
+        # Confirmed as still in-use in 2017.
+        # Got conferred with 'the Great' title in 2019 (B.E. 2562).
 
-        if year >= 1960:
+        if 1960 <= year <= 2015:
+            _add_with_observed(
+                date(year, DEC, 5),
+                self.tr(
+                    "วันเฉลิมพระชนมพรรษา"
+                    "พระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+                ),
+            )
+        elif 2016 <= year <= 2018:
+            _add_with_observed(
+                date(year, DEC, 5),
+                self.tr(
+                    "วันคล้ายวันเฉลิมพระชนมพรรษา"
+                    "พระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+                ),
+            )
+        elif year >= 2019:
             _add_with_observed(
-                date(year, DEC, 5), "HM King Bhumibol Adulyadej's Birthday"
+                date(year, DEC, 5),
+                self.tr(
+                    "วันคล้ายวันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระบรมชนกาธิเบศร "
+                    "มหาภูมิพลอดุลยเดชมหาราช บรมนาถบพิตร"
+                ),
             )
 
-        # !!! National Father's Day !!!
+        # National Father's Day.
         # วันพ่อแห่งชาติ
-        # Status: In-Use
-        # Starts in 1980 (B.E 2523)
+        # Status: In-Use.
+        # Starts in 1980 (B.E 2523).
         # Technically, a replication of HM King Bhumibol Adulyadej's Birthday
-        #   but it's in the official calendar, so may as well have this here
+        #   but it's in the official calendar, so may as well have this here.
 
         if year >= 1980:
-            _add_with_observed(date(year, DEC, 5), "National Father's Day")
+            _add_with_observed(date(year, DEC, 5), self.tr("วันพ่อแห่งชาติ"))
 
-        # !!! Constitution Day !!!
+        # Constitution Day.
         # วันรัฐธรรมนูญ
-        # Status: In-Use
-        # Presumed to starts in 1932 (B.E. 2475) ???
-        # Last known official record is Bank of Thailand's in 1992 (B.E. 2535)
+        # Status: In-Use.
+        # Presumed to starts in 1932 (B.E. 2475).
+        # Last known official record is Bank of Thailand's in 1992 (B.E. 2535).
         # TODO: Add check for 1932 if we support earlier dates.
 
-        _add_with_observed(date(year, DEC, 10), "Constitution Day")
+        _add_with_observed(date(year, DEC, 10), self.tr("วันรัฐธรรมนูญ"))
 
-        # !!! New Year's Eve !!!
+        # New Year's Eve.
         # วันสิ้นปี
-        # Status: In-Use
-        # Presumed to start in the present form in 1941 (B.E. 2484) ???
-        # Last known official record is Bank of Thailand's in 1992 (B.E. 2535)
+        # Status: In-Use.
+        # Presumed to start in the present form in 1941 (B.E. 2484).
+        # Last known official record is Bank of Thailand's in 1992 (B.E. 2535).
         # TODO: Add check for 1941 if we support earlier dates.
-        # This has its own in-lieu trigger
+        # This has its own in-lieu trigger.
 
-        self[date(year, DEC, 31)] = "New Year's Eve"
+        self[date(year, DEC, 31)] = self.tr("วันสิ้นปี")
 
-        ################################
-        #
-        # THAI LUNAR CALENDAR HOLIDAYS
-        #
-        ################################
+        # Thai Lunar Calendar Holidays
 
         """
         See `_ThaiLuniSolar` in holidays/utils.py for more details.
@@ -526,48 +580,48 @@ def _add_with_observed(dt, holiday_name) -> None:
         Thai Lunar Calendar Holidays only work from 1941 (B.E. 2484) onwards
         until 2057 (B.E. 2600).
         """
-        # !!! Makha Bucha !!!
+        # Makha Bucha.
         # วันมาฆบูชา
-        # Status: In-Use
+        # Status: In-Use.
 
         makha_bucha_date = self.thls.makha_bucha_date(year)
         if makha_bucha_date:
-            _add_with_observed(makha_bucha_date, "Makha Bucha")
+            _add_with_observed(makha_bucha_date, self.tr("วันมาฆบูชา"))
 
-        # !!! Visakha Bucha !!!
+        # Visakha Bucha.
         # วันวิสาขบูชา
-        # Status: In-Use
+        # Status: In-Use.
 
         visakha_bucha_date = self.thls.visakha_bucha_date(year)
         if visakha_bucha_date:
-            _add_with_observed(visakha_bucha_date, "Visakha Bucha")
+            _add_with_observed(visakha_bucha_date, self.tr("วันวิสาขบูชา"))
 
-        # !!! Asarnha Bucha !!!
+        # Asarnha Bucha.
         # วันอาสาฬหบูชา
-        # Status: In-Use
-        # This has its own in-lieu trigger
+        # Status: In-Use.
+        # This has its own in-lieu trigger.
 
         asarnha_bucha_date = self.thls.asarnha_bucha_date(year)
         if asarnha_bucha_date:
-            self[asarnha_bucha_date] = "Asarnha Bucha"
+            self[asarnha_bucha_date] = self.tr("วันอาสาฬหบูชา")
 
-        # !!! Buddhist Lent Day !!!
+        # Buddhist Lent Day.
         # วันเข้าพรรษา
-        # Status: In-Use
-        # This has its own in-lieu trigger
+        # Status: In-Use.
+        # This has its own in-lieu trigger.
 
         khao_phansa_date = self.thls.khao_phansa_date(year)
         if khao_phansa_date:
-            self[khao_phansa_date] = "Buddhist Lent Day"
+            self[khao_phansa_date] = self.tr("วันเข้าพรรษา")
 
-        # !!! Asarnha Bucha/Buddhist Lent Day (in lieu) !!!
+        # Asarnha Bucha/Buddhist Lent Day (in lieu).
         # วันหยุดชดเชยวันอาสาฬหบูชา
         # วันหยุดชดเชยวันเข้าพรรษา
-        # Status: In Use
+        # Status: In Use.
         #  - CASE 1: FRI-SAT -> 1 in-lieu on MON
         #  - CASE 2: SAT-SUN -> 1 in-lieu on MON
         #  - CASE 3: SUN-MON -> 1 in-lieu on TUE
-        # See in lieu logic in `_add_with_observed(dt, holiday_name)`
+        # See in lieu logic in `_add_with_observed(dt, holiday_name)`.
 
         if (
             asarnha_bucha_date
@@ -575,35 +629,32 @@ def _add_with_observed(dt, holiday_name) -> None:
             and (1961 <= year <= 1973 or 1995 <= year <= 1997 or year >= 2001)
         ):
             if self._is_friday(asarnha_bucha_date):
-                self[
-                    asarnha_bucha_date + td(days=+3)
-                ] = "Buddhist Lent Day (in lieu)"
+                self[asarnha_bucha_date + td(days=+3)] = self.tr(
+                    "ชดเชย%s"
+                ) % self.tr("วันเข้าพรรษา")
             elif self._is_weekend(asarnha_bucha_date):
-                self[
-                    asarnha_bucha_date + td(days=+2)
-                ] = "Asarnha Bucha (in lieu)"
+                self[asarnha_bucha_date + td(days=+2)] = self.tr(
+                    "ชดเชย%s"
+                ) % self.tr("วันอาสาฬหบูชา")
 
-        #################################
-        #
-        # NO FUTURE FIXED DATE HOLIDAYS
-        #
-        #################################
+        # No Future Fixed Date Holidays
 
-        # !!! Royal Ploughing Ceremony !!!
+        # Royal Ploughing Ceremony.
         # วันพืชมงคล
-        # Restarts in 1957 (B.E. 2500)
-        # Is dated on an annual basis by the Royal Palace
+        # Restarts in 1957 (B.E. 2500).
+        # Is dated on an annual basis by the Royal Palace.
         # This isn't even fixed even by the Thai Lunar Calendar, but instead
         #   by Court Astrologers; All chosen dates are all around May, so we
         #   can technically assign it to 13 May for years prior with no data.
-        # *** NOTE: only observed by government sectors
-        # TODO: Update this annually around Dec of each year
-        raeknakhwan = "Royal Ploughing Ceremony"
+        # *** NOTE: only observed by government sectors.
+        # TODO: Update this annually around Dec of each year.
+
+        raeknakhwan = self.tr("วันพืชมงคล")
 
         raeknakhwan_dates = {
             1997: (MAY, 13),
             1998: (MAY, 13),
-            # Not held in 1999 date
+            # Not held in 1999 date.
             2000: (MAY, 15),
             2001: (MAY, 16),
             2002: (MAY, 9),
@@ -629,12 +680,12 @@ def _add_with_observed(dt, holiday_name) -> None:
             2022: (MAY, 17),
             2023: (MAY, 11),
         }
-        # For years with exact date data
+        # For years with exact date data.
         if year in raeknakhwan_dates:
             _add_with_observed(
                 date(year, *raeknakhwan_dates[year]), raeknakhwan
             )
-        # Approx. otherwise for 1957-2013
+        # Approx. otherwise for 1957-2013.
         elif 1957 <= year <= 1996:
             _add_with_observed(date(year, MAY, 13), raeknakhwan)
 
diff --git a/holidays/countries/tunisia.py b/holidays/countries/tunisia.py
index 2bbe7adbc..3bbdd88f5 100644
--- a/holidays/countries/tunisia.py
+++ b/holidays/countries/tunisia.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, APR, MAY, JUL, AUG, OCT
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Tunisia(HolidayBase):
diff --git a/holidays/countries/turkey.py b/holidays/countries/turkey.py
index b73801e00..f539c4a77 100644
--- a/holidays/countries/turkey.py
+++ b/holidays/countries/turkey.py
@@ -12,9 +12,9 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, APR, MAY, JUL, AUG, OCT
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Turkey(HolidayBase):
diff --git a/holidays/countries/united_arab_emirates.py b/holidays/countries/united_arab_emirates.py
index 33825d87f..a0ae172ee 100644
--- a/holidays/countries/united_arab_emirates.py
+++ b/holidays/countries/united_arab_emirates.py
@@ -12,10 +12,10 @@
 from datetime import date
 from datetime import timedelta as td
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, APR, MAY, JUN, JUL, AUG, SEP, NOV, DEC
 from holidays.constants import FRI, SAT
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class UnitedArabEmirates(HolidayBase):
diff --git a/holidays/countries/united_kingdom.py b/holidays/countries/united_kingdom.py
index 3bd4fc041..08c480ee5 100644
--- a/holidays/countries/united_kingdom.py
+++ b/holidays/countries/united_kingdom.py
@@ -14,10 +14,10 @@
 from typing import Any
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAR, APR, MAY, JUN, JUL, AUG, SEP, NOV, DEC
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
+from holidays.constants import JAN, MAR, APR, MAY, JUN, JUL, AUG, SEP, NOV
+from holidays.constants import DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -60,7 +60,7 @@ def _populate(self, year: int) -> None:
             dt = date(year, JAN, 1)
             self[dt] = name
             if self.observed and self._is_weekend(dt):
-                self[dt + rd(weekday=MO)] = name + " (Observed)"
+                self[_get_nth_weekday_from(1, MON, dt)] = name + " (Observed)"
 
         # New Year Holiday
         if self.subdiv in {"Scotland", "UK"}:
@@ -82,7 +82,7 @@ def _populate(self, year: int) -> None:
                 name += " [Northern Ireland]"
             self[dt] = name
             if self.observed and self._is_weekend(dt):
-                self[dt + rd(weekday=MO)] = name + " (Observed)"
+                self[_get_nth_weekday_from(1, MON, dt)] = name + " (Observed)"
 
         # Battle of the Boyne
         if self.subdiv in {"Northern Ireland", "UK"}:
@@ -96,7 +96,7 @@ def _populate(self, year: int) -> None:
             name = "Summer Bank Holiday"
             if self.subdiv == "UK":
                 name += " [Scotland]"
-            self[date(year, AUG, 1) + rd(weekday=MO)] = name
+            self[_get_nth_weekday_of_month(1, MON, AUG, year)] = name
 
         # St. Andrew's Day
         if self.subdiv in {"Scotland", "UK"}:
@@ -138,7 +138,7 @@ def _country_specific(self, year: int) -> None:
                 # In 2020 moved to Friday to mark 75th anniversary of VE Day.
                 dt = date(year, MAY, 8)
             else:
-                dt = date(year, MAY, 1) + rd(weekday=MO)
+                dt = _get_nth_weekday_of_month(1, MON, MAY, year)
             self[dt] = name
 
         # Spring bank holiday (last Monday in May)
@@ -148,14 +148,14 @@ def _country_specific(self, year: int) -> None:
         elif year == 2022:
             self[date(year, JUN, 2)] = name
         elif year >= 1971:
-            self[date(year, MAY, 31) + rd(weekday=MO(-1))] = name
+            self[_get_nth_weekday_of_month(-1, MON, MAY, year)] = name
 
         # Late Summer bank holiday (last Monday in August)
         if self.subdiv != "Scotland" and year >= 1971:
             name = "Late Summer Bank Holiday"
             if self.subdiv == "UK":
                 name += " [England/Wales/Northern Ireland]"
-            self[date(year, AUG, 31) + rd(weekday=MO(-1))] = name
+            self[_get_nth_weekday_of_month(-1, MON, AUG, year)] = name
 
         # Boxing Day
         name = "Boxing Day"
diff --git a/holidays/countries/united_states.py b/holidays/countries/united_states.py
index 8fdfb8427..a41a3e5eb 100644
--- a/holidays/countries/united_states.py
+++ b/holidays/countries/united_states.py
@@ -13,11 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO, TU, TH, FR
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _get_nth_weekday_from, _get_nth_weekday_of_month
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
-from holidays.constants import OCT, NOV, DEC
+from holidays.constants import OCT, NOV, DEC, MON, TUE, THU, FRI
 from holidays.holiday_base import HolidayBase
 
 
@@ -130,10 +129,10 @@ def _populate(self, year):
         if self.subdiv == "VA" and year <= 2020:
             name = "Lee Jackson Day"
             if year >= 2000:
-                dt = date(year, JAN, 1) + rd(weekday=MO(+3)) + td(days=-3)
+                dt = _get_nth_weekday_of_month(3, MON, JAN, year) + td(days=-3)
                 self[dt] = name
             elif year >= 1983:
-                self[date(year, JAN, 1) + rd(weekday=MO(+3))] = name
+                self[_get_nth_weekday_of_month(3, MON, JAN, year)] = name
             elif year >= 1889:
                 self[date(year, JAN, 19)] = name
 
@@ -167,7 +166,7 @@ def _populate(self, year):
                 name = "Robert E. Lee's Birthday"
             elif self.subdiv == "ID" and year >= 2006:
                 name = "Martin Luther King Jr. - Idaho Human Rights Day"
-            self[date(year, JAN, 1) + rd(weekday=MO(+3))] = name
+            self[_get_nth_weekday_of_month(3, MON, JAN, year)] = name
 
         # Lincoln's Birthday
         if (
@@ -194,7 +193,7 @@ def _populate(self, year):
             name = "Presidents' Day"
         if self.subdiv not in {"DE", "FL", "GA", "NM", "PR"}:
             if year >= 1971:
-                self[date(year, FEB, 1) + rd(weekday=MO(+3))] = name
+                self[_get_nth_weekday_of_month(3, MON, FEB, year)] = name
             elif year >= 1879:
                 self[date(year, FEB, 22)] = name
         elif self.subdiv == "GA":
@@ -203,7 +202,7 @@ def _populate(self, year):
             else:
                 self[date(year, DEC, 26)] = name
         elif self.subdiv in {"PR", "VI"}:
-            self[date(year, FEB, 1) + rd(weekday=MO(+3))] = name
+            self[_get_nth_weekday_of_month(3, MON, FEB, year)] = name
 
         easter_date = easter(year)
         # Mardi Gras
@@ -212,11 +211,15 @@ def _populate(self, year):
 
         # Guam Discovery Day
         if self.subdiv == "GU" and year >= 1970:
-            self[date(year, MAR, 1) + rd(weekday=MO)] = "Guam Discovery Day"
+            self[
+                _get_nth_weekday_of_month(1, MON, MAR, year)
+            ] = "Guam Discovery Day"
 
         # Casimir Pulaski Day
         if self.subdiv == "IL" and year >= 1978:
-            self[date(year, MAR, 1) + rd(weekday=MO)] = "Casimir Pulaski Day"
+            self[
+                _get_nth_weekday_of_month(1, MON, MAR, year)
+            ] = "Casimir Pulaski Day"
 
         # Texas Independence Day
         if self.subdiv == "TX" and year >= 1874:
@@ -224,7 +227,9 @@ def _populate(self, year):
 
         # Town Meeting Day
         if self.subdiv == "VT" and year >= 1800:
-            self[date(year, MAR, 1) + rd(weekday=TU)] = "Town Meeting Day"
+            self[
+                _get_nth_weekday_of_month(1, TUE, MAR, year)
+            ] = "Town Meeting Day"
 
         # Evacuation Day
         if self.subdiv == "MA" and year >= 1901:
@@ -232,7 +237,7 @@ def _populate(self, year):
             dt = date(year, MAR, 17)
             self[dt] = name
             if self.observed and self._is_weekend(dt):
-                self[dt + rd(weekday=MO)] = f"{name} (Observed)"
+                self[_get_nth_weekday_from(1, MON, dt)] = f"{name} (Observed)"
 
         # Emancipation Day
         if self.subdiv == "PR":
@@ -256,7 +261,7 @@ def _populate(self, year):
         if self.subdiv == "AK":
             name = "Seward's Day"
             if year >= 1955:
-                self[date(year, MAR, 31) + rd(weekday=MO(-1))] = name
+                self[_get_nth_weekday_of_month(-1, MON, MAR, year)] = name
             elif year >= 1918:
                 self[date(year, MAR, 30)] = name
 
@@ -280,7 +285,7 @@ def _populate(self, year):
         if self.subdiv in {"MA", "ME"}:
             name = "Patriots' Day"
             if year >= 1969:
-                self[date(year, APR, 1) + rd(weekday=MO(+3))] = name
+                self[_get_nth_weekday_of_month(3, MON, APR, year)] = name
             elif year >= 1894:
                 self[date(year, APR, 19)] = name
 
@@ -318,7 +323,7 @@ def _populate(self, year):
             if self.subdiv == "GA" and year == 2020:
                 self[date(year, APR, 10)] = name
             else:
-                self[date(year, APR, 1) + rd(weekday=MO(+4))] = name
+                self[_get_nth_weekday_of_month(4, MON, APR, year)] = name
         elif self.subdiv == "TX" and year >= 1931:
             self[date(year, JAN, 19)] = name
 
@@ -330,7 +335,7 @@ def _populate(self, year):
         if self.subdiv == "NE":
             name = "Arbor Day"
             if year >= 1989:
-                self[date(year, APR, 30) + rd(weekday=FR(-1))] = name
+                self[_get_nth_weekday_of_month(-1, FRI, APR, year)] = name
             elif year >= 1875:
                 self[date(year, APR, 22)] = name
 
@@ -339,7 +344,7 @@ def _populate(self, year):
             (year >= 2006 and year % 2 == 0) or year >= 2015
         ):
             self[
-                (date(year, MAY, 1) + rd(weekday=MO) + td(days=+1))
+                _get_nth_weekday_of_month(1, MON, MAY, year) + td(days=+1)
             ] = "Primary Election Day"
 
         # Truman Day
@@ -348,7 +353,9 @@ def _populate(self, year):
 
         # Memorial Day
         if year >= 1971:
-            self[date(year, MAY, 31) + rd(weekday=MO(-1))] = "Memorial Day"
+            self[
+                _get_nth_weekday_of_month(-1, MON, MAY, year)
+            ] = "Memorial Day"
         elif year >= 1888:
             self[date(year, MAY, 30)] = "Memorial Day"
 
@@ -361,7 +368,7 @@ def _populate(self, year):
         # Jefferson Davis Birthday
         name = "Jefferson Davis Birthday"
         if self.subdiv == "AL" and year >= 1890:
-            self[date(year, JUN, 1) + rd(weekday=MO)] = name
+            self[_get_nth_weekday_of_month(1, MON, JUN, year)] = name
 
         # Kamehameha Day
         if self.subdiv == "HI" and year >= 1872:
@@ -404,11 +411,13 @@ def _populate(self, year):
 
         # Victory Day
         if self.subdiv == "RI" and year >= 1948:
-            self[date(year, AUG, 1) + rd(weekday=MO(+2))] = "Victory Day"
+            self[_get_nth_weekday_of_month(2, MON, AUG, year)] = "Victory Day"
 
         # Statehood Day (Hawaii)
         if self.subdiv == "HI" and year >= 1959:
-            self[date(year, AUG, 1) + rd(weekday=FR(+3))] = "Statehood Day"
+            self[
+                _get_nth_weekday_of_month(3, FRI, AUG, year)
+            ] = "Statehood Day"
 
         # Bennington Battle Day
         if self.subdiv == "VT" and year >= 1778:
@@ -422,7 +431,7 @@ def _populate(self, year):
 
         # Labor Day
         if year >= 1894:
-            self[date(year, SEP, 1) + rd(weekday=MO)] = "Labor Day"
+            self[_get_nth_weekday_of_month(1, MON, SEP, year)] = "Labor Day"
 
         # Columbus Day
         if self.subdiv not in {"AK", "AR", "DE", "FL", "HI", "NV"}:
@@ -433,14 +442,14 @@ def _populate(self, year):
             else:
                 name = "Columbus Day"
             if year >= 1970:
-                self[date(year, OCT, 1) + rd(weekday=MO(+2))] = name
+                self[_get_nth_weekday_of_month(2, MON, OCT, year)] = name
             elif year >= 1937:
                 self[date(year, OCT, 12)] = name
 
         # Commonwealth Cultural Day in Northern Mariana Islands
         if self.subdiv == "MP":
             self[
-                date(year, OCT, 1) + rd(weekday=MO(+2))
+                _get_nth_weekday_of_month(2, MON, OCT, year)
             ] = "Commonwealth Cultural Day"
 
         # Alaska Day
@@ -451,7 +460,7 @@ def _populate(self, year):
         if self.subdiv == "NV" and year >= 1933:
             dt = date(year, OCT, 31)
             if year >= 2000:
-                dt += rd(weekday=FR(-1))
+                dt = _get_nth_weekday_of_month(-1, FRI, OCT, year)
             self._add_with_observed(dt, "Nevada Day")
 
         # Liberty Day
@@ -478,7 +487,7 @@ def _populate(self, year):
             and year % 2 == 0
         ) or (self.subdiv in {"IN", "NY"} and year >= 2015):
             self[
-                date(year, NOV, 1) + rd(weekday=MO) + td(days=+1)
+                _get_nth_weekday_of_month(1, MON, NOV, year) + td(days=+1)
             ] = "Election Day"
 
         # All Souls' Day
@@ -495,7 +504,7 @@ def _populate(self, year):
         else:
             name = "Armistice Day"
         if 1971 <= year <= 1977:
-            self[date(year, OCT, 1) + rd(weekday=MO(+4))] = name
+            self[_get_nth_weekday_of_month(4, MON, OCT, year)] = name
         elif year >= 1938:
             self._add_with_observed(date(year, NOV, 11), name)
 
@@ -507,7 +516,7 @@ def _populate(self, year):
 
         # Thanksgiving
         if year >= 1871:
-            self[date(year, NOV, 1) + rd(weekday=TH(+4))] = "Thanksgiving"
+            self[_get_nth_weekday_of_month(4, THU, NOV, year)] = "Thanksgiving"
 
         # Day After Thanksgiving
         # Friday After Thanksgiving
@@ -536,7 +545,9 @@ def _populate(self, year):
                 name = "Family Day"
             if self.subdiv == "NM":
                 name = "Presidents' Day"
-            self[date(year, NOV, 1) + rd(weekday=TH(+4)) + td(days=+1)] = name
+            self[
+                _get_nth_weekday_of_month(4, THU, NOV, year) + td(days=+1)
+            ] = name
 
         # Robert E. Lee's Birthday
         if self.subdiv == "GA" and year >= 1986:
@@ -544,7 +555,9 @@ def _populate(self, year):
                 name = "State Holiday"
             else:
                 name = "Robert E. Lee's Birthday"
-            self[date(year, NOV, 29) + rd(weekday=FR(-1))] = name
+            self[
+                _get_nth_weekday_of_month(4, THU, NOV, year) + td(days=+1)
+            ] = name
 
         # Lady of Camarin Day
         if self.subdiv == "GU":
@@ -569,7 +582,7 @@ def _populate(self, year):
                 self[dt + td(days=-1)] = f"{name} (Observed)"
             # If on Saturday or Sunday, observed on Friday
             elif self.observed and self._is_weekend(dt):
-                self[dt + rd(weekday=FR(-1))] = f"{name} (Observed)"
+                self[_get_nth_weekday_from(-1, FRI, dt)] = f"{name} (Observed)"
 
         # Christmas Day
         if year >= 1871:
@@ -582,7 +595,7 @@ def _populate(self, year):
             self[dt] = name
             # If on Saturday or Sunday, observed on Monday
             if self.observed and self._is_weekend(dt):
-                self[dt + rd(weekday=MO)] = f"{name} (Observed)"
+                self[_get_nth_weekday_from(1, MON, dt)] = f"{name} (Observed)"
             # If on Monday, observed on Tuesday
             elif self.observed and self._is_monday(dt):
                 self[dt + td(days=+1)] = f"{name} (Observed)"
diff --git a/holidays/countries/uruguay.py b/holidays/countries/uruguay.py
index ca78df24b..9233923a5 100644
--- a/holidays/countries/uruguay.py
+++ b/holidays/countries/uruguay.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, APR, MAY, JUN, JUL, AUG, OCT, NOV, DEC
+from holidays.calendars import _get_nth_weekday_from
+from holidays.constants import JAN, APR, MAY, JUN, JUL, AUG, OCT, NOV, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -105,9 +104,9 @@ def _populate(self, year):
 
         for dt, name in holiday_pairs:
             if self._is_tuesday(dt) or self._is_wednesday(dt):
-                self[dt + rd(weekday=MO(-1))] = name
+                self[_get_nth_weekday_from(-1, MON, dt)] = name
             elif self._is_thursday(dt) or self._is_friday(dt):
-                self[dt + rd(weekday=MO(+1))] = name
+                self[_get_nth_weekday_from(1, MON, dt)] = name
             else:
                 self[dt] = name
 
diff --git a/holidays/countries/uzbekistan.py b/holidays/countries/uzbekistan.py
index 0c305281a..83d3ae6d1 100644
--- a/holidays/countries/uzbekistan.py
+++ b/holidays/countries/uzbekistan.py
@@ -11,9 +11,9 @@
 
 from datetime import date
 
+from holidays.calendars import _islamic_to_gre
 from holidays.constants import JAN, MAR, MAY, SEP, OCT, DEC
 from holidays.holiday_base import HolidayBase
-from holidays.utils import _islamic_to_gre
 
 
 class Uzbekistan(HolidayBase):
diff --git a/holidays/countries/zambia.py b/holidays/countries/zambia.py
index 81c61729a..408fd7e20 100644
--- a/holidays/countries/zambia.py
+++ b/holidays/countries/zambia.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, MAR, APR, MAY, JUL, AUG, SEP, OCT, DEC
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, MAR, APR, MAY, JUL, AUG, SEP, OCT, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -86,12 +85,12 @@ def _add_with_observed(hol_date: date, hol_name: str) -> None:
         _add_with_observed(date(year, MAY, 25), "Africa Freedom Day")
 
         # 1st Monday of July = "Heroes' Day"
-        dt = date(year, JUL, 1) + rd(weekday=MO)
+        dt = _get_nth_weekday_of_month(1, MON, JUL, year)
         self[dt] = "Heroes' Day"
         self[dt + td(days=+1)] = "Unity Day"
 
         # 1st Monday of Aug = "Farmers' Day"
-        self[date(year, AUG, 1) + rd(weekday=MO)] = "Farmers' Day"
+        self[_get_nth_weekday_of_month(1, MON, AUG, year)] = "Farmers' Day"
 
         if year >= 2015:
             _add_with_observed(date(year, OCT, 18), "National Prayer Day")
diff --git a/holidays/countries/zimbabwe.py b/holidays/countries/zimbabwe.py
index 309bf5ce6..af7e59f49 100644
--- a/holidays/countries/zimbabwe.py
+++ b/holidays/countries/zimbabwe.py
@@ -13,10 +13,9 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO
-from dateutil.relativedelta import relativedelta as rd
 
-from holidays.constants import JAN, FEB, APR, MAY, AUG, DEC
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import JAN, FEB, APR, MAY, AUG, DEC, MON
 from holidays.holiday_base import HolidayBase
 
 
@@ -66,7 +65,7 @@ def _add_with_observed(
         _add_with_observed(date(year, MAY, 25), "Africa Day")
 
         # 2nd Monday of August
-        zimbabwe_heroes_day = date(year, AUG, 1) + rd(weekday=MO(+2))
+        zimbabwe_heroes_day = _get_nth_weekday_of_month(2, MON, AUG, year)
         self[zimbabwe_heroes_day] = "Zimbabwe Heroes' Day"
 
         # Tuesday after 2nd Monday of August
diff --git a/holidays/financial/ny_stock_exchange.py b/holidays/financial/ny_stock_exchange.py
index 33512bf25..6fa83581a 100644
--- a/holidays/financial/ny_stock_exchange.py
+++ b/holidays/financial/ny_stock_exchange.py
@@ -13,11 +13,10 @@
 from datetime import timedelta as td
 
 from dateutil.easter import easter
-from dateutil.relativedelta import MO, TH, FR
-from dateutil.relativedelta import relativedelta as rd
 
+from holidays.calendars import _get_nth_weekday_of_month
 from holidays.constants import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP
-from holidays.constants import OCT, NOV, DEC
+from holidays.constants import OCT, NOV, DEC, MON, THU
 from holidays.holiday_base import HolidayBase
 
 
@@ -33,20 +32,13 @@ class NewYorkStockExchange(HolidayBase):
     def __init__(self, **kwargs):
         HolidayBase.__init__(self, **kwargs)
 
-    def _get_observed(self, d):
-        wdnum = d.isoweekday()
-        if wdnum == 6:
-            return d + rd(weekday=FR(-1))
-        if wdnum == 7:
-            return d + rd(weekday=MO(+1))
-        return d
-
-    def _set_observed_date(self, holiday_date, name):
-        date_obs = self._get_observed(holiday_date)
-        if date_obs == holiday_date:
-            self[holiday_date] = name
+    def _set_observed_date(self, holiday_date: date, name: str) -> None:
+        if self._is_saturday(holiday_date):
+            self[holiday_date + td(days=-1)] = name + " (Observed)"
+        elif self._is_sunday(holiday_date):
+            self[holiday_date + td(days=+1)] = name + " (Observed)"
         else:
-            self[date_obs] = name + " (Observed)"
+            self[holiday_date] = name
 
     def _populate(self, year):
         super()._populate(year)
@@ -57,7 +49,9 @@ def _populate(self, year):
 
         # NYD
         # This year's New Year Day.
-        self._set_observed_date(date(year, JAN, 1), "New Year's Day")
+        jan_1 = date(year, JAN, 1)
+        if not self._is_saturday(jan_1):
+            self._set_observed_date(jan_1, "New Year's Day")
 
         # https://www.nyse.com/publicdocs/nyse/regulation/nyse/NYSE_Rules.pdf
         # As per Rule 7.2.: check if next year's NYD falls on Saturday and
@@ -69,7 +63,7 @@ def _populate(self, year):
         # MLK - observed 1998 - 3rd Monday of Jan
         if year >= 1998:
             self[
-                date(year, JAN, 1) + rd(weekday=MO(3))
+                _get_nth_weekday_of_month(3, MON, JAN, year)
             ] = "Martin Luther King Jr. Day"
 
         # LINCOLN BIRTHDAY: observed 1896 - 1953 and 1968, Feb 12 (observed)
@@ -83,7 +77,7 @@ def _populate(self, year):
             self._set_observed_date(wash, "Washington's Birthday")
         else:
             self[
-                date(year, FEB, 1) + rd(weekday=MO(3))
+                _get_nth_weekday_of_month(3, MON, FEB, year)
             ] = "Washington's Birthday"
 
         # GOOD FRIDAY - closed every year except 1898, 1906, and 1907
@@ -97,7 +91,9 @@ def _populate(self, year):
             memday = date(year, MAY, 30)
             self._set_observed_date(memday, "Memorial Day")
         else:
-            self[date(year, MAY, 31) + rd(weekday=MO(-1))] = "Memorial Day"
+            self[
+                _get_nth_weekday_of_month(-1, MON, MAY, year)
+            ] = "Memorial Day"
 
         # FLAG DAY: June 14th 1916 - 1953
         if 1916 <= year <= 1953:
@@ -117,7 +113,7 @@ def _populate(self, year):
 
         # LABOR DAY - first mon in Sept, since 1887
         if year >= 1887:
-            self[date(year, SEP, 1) + rd(weekday=MO(1))] = "Labor Day"
+            self[_get_nth_weekday_of_month(1, MON, SEP, year)] = "Labor Day"
 
         # COLUMBUS DAY/INDIGENOUS PPL DAY: Oct 12 - closed 1909-1953
         if 1909 <= year <= 1953:
@@ -128,7 +124,7 @@ def _populate(self, year):
         # closed until 1969, then closed pres years 1972-80
         if year <= 1968 or year in {1972, 1976, 1980}:
             self[
-                date(year, NOV, 1) + rd(weekday=MO) + td(days=+1)
+                _get_nth_weekday_of_month(1, MON, NOV, year) + td(days=+1)
             ] = "Election Day"
 
         # VETERAN'S DAY: Nov 11 - closed 1918, 1921, 1934-1953
@@ -137,7 +133,7 @@ def _populate(self, year):
             self._set_observed_date(vetday, "Veteran's Day")
 
         # THXGIVING DAY: 4th Thurs in Nov - closed every year
-        self[date(year, NOV, 1) + rd(weekday=TH(4))] = "Thanksgiving Day"
+        self[_get_nth_weekday_of_month(4, THU, NOV, year)] = "Thanksgiving Day"
 
         # XMAS DAY: Dec 25th - every year
         xmas = date(year, DEC, 25)
diff --git a/holidays/holiday_base.py b/holidays/holiday_base.py
index 501d9d128..6f6f48ee6 100644
--- a/holidays/holiday_base.py
+++ b/holidays/holiday_base.py
@@ -528,20 +528,56 @@ def get_list(self, key: DateLike) -> List[str]:
             if name
         ]
 
-    def get_named(self, name: str) -> List[date]:
+    def get_named(self, holiday_name: str, lookup="icontains") -> List[date]:
         """Return a list of all holiday dates matching the provided holiday
         name. The match will be made case insensitively and partial matches
-        will be included.
+        will be included by default.
 
-        :param name:
+        :param holiday_name:
             The holiday's name to try to match.
+        :param lookup:
+            The holiday name lookup type:
+                contains - case sensitive contains match;
+                exact - case sensitive exact match;
+                icontains - case insensitive contains match;
+                iexact - case insensitive exact match;
 
         :return:
             A list of all holiday dates matching the provided holiday name.
         """
-        return [
-            key for key, value in self.items() if name.lower() in value.lower()
-        ]
+        holiday_date_names_mapping: Dict[date, List[str]] = {
+            key: value.split(HOLIDAY_NAME_DELIMITER)
+            for key, value in self.items()
+        }
+
+        if lookup == "icontains":
+            holiday_name_lower = holiday_name.lower()
+            return [
+                dt
+                for dt, names in holiday_date_names_mapping.items()
+                if any((holiday_name_lower in name.lower() for name in names))
+            ]
+        elif lookup == "exact":
+            return [
+                dt
+                for dt, names in holiday_date_names_mapping.items()
+                if any((holiday_name == name for name in names))
+            ]
+        elif lookup == "contains":
+            return [
+                dt
+                for dt, names in holiday_date_names_mapping.items()
+                if any((holiday_name in name for name in names))
+            ]
+        elif lookup == "iexact":
+            holiday_name_lower = holiday_name.lower()
+            return [
+                dt
+                for dt, names in holiday_date_names_mapping.items()
+                if any((holiday_name_lower == name.lower() for name in names))
+            ]
+
+        raise AttributeError(f"Unknown lookup type: {lookup}")
 
     def pop(
         self,
diff --git a/holidays/locale/en_US/LC_MESSAGES/AR.po b/holidays/locale/en_US/LC_MESSAGES/AR.po
index 424758ec3..5fd764a40 100644
--- a/holidays/locale/en_US/LC_MESSAGES/AR.po
+++ b/holidays/locale/en_US/LC_MESSAGES/AR.po
@@ -4,9 +4,9 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: Python Holidays 0.20\n"
-"POT-Creation-Date: 2023-02-15 08:13-0800\n"
-"PO-Revision-Date: 2022-12-15 21:42-0800\n"
-"Last-Translator: Arkadii Yakovets <ark@cho.red>\n"
+"POT-Creation-Date: 2023-03-02 00:39+0700\n"
+"PO-Revision-Date: 2023-02-20 19:10+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
 "Language-Team: Python Holidays localization team\n"
 "Language: en_US\n"
 "MIME-Version: 1.0\n"
@@ -16,85 +16,111 @@ msgstr ""
 "Generated-By: pygettext.py 1.5\n"
 "X-Generator: Poedit 3.2.2\n"
 
-#: holidays/countries/argentina.py:41
+#: holidays/countries/argentina.py:71
+msgid "Feriado con fines turísticos"
+msgstr "Bridge Public Holiday"
+
+#: holidays/countries/argentina.py:75
+msgid "Bicentenario de la creación y primera jura de la bandera nacional"
+msgstr "Bicentenary of the creation and first oath of the national flag"
+
+#: holidays/countries/argentina.py:78
+msgid "Bicentenario de la Batalla de Tucumán"
+msgstr "Bicentenary of the Battle of Tucumán"
+
+#: holidays/countries/argentina.py:79
+msgid ""
+"Bicentenario de la sesión inaugural de la Asamblea Nacional Constituyente "
+"del año 1813"
+msgstr ""
+"Bicentenary of the inaugural session of the National Constituent Assembly of "
+"the year 1813"
+
+#: holidays/countries/argentina.py:83
+msgid "Bicentenario de la Batalla de Salta"
+msgstr "Bicentenary of the Battle of Salta"
+
+#: holidays/countries/argentina.py:84
+msgid "Censo nacional 2022"
+msgstr "National Census Day 2022"
+
+#: holidays/countries/argentina.py:162 holidays/countries/argentina.py:165
+#, c-format
+msgid "%s (Observado)"
+msgstr "%s (Observed)"
+
+#: holidays/countries/argentina.py:177
 msgid "Año Nuevo"
 msgstr "New Year's Day"
 
-#. Carnival days
-#: holidays/countries/argentina.py:45
+#: holidays/countries/argentina.py:185
 msgid "Día de Carnaval"
 msgstr "Carnival"
 
-#. Memory's National Day for the Truth and Justice
-#: holidays/countries/argentina.py:50
+#: holidays/countries/argentina.py:194
 msgid "Día Nacional de la Memoria por la Verdad y la Justicia"
 msgstr "Memory's National Day for the Truth and Justice"
 
-#. Holy Week
-#: holidays/countries/argentina.py:60
-msgid "Semana Santa (Jueves Santo)"
-msgstr "Holy Thursday"
-
-#: holidays/countries/argentina.py:61
-msgid "Semana Santa (Viernes Santo)"
-msgstr "Holy Friday"
+#: holidays/countries/argentina.py:209
+msgid "Día del Veterano de Guerra"
+msgstr "War Veterans Day"
 
-#: holidays/countries/argentina.py:62
-msgid "Día de Pascuas"
-msgstr "Easter Sunday"
-
-#: holidays/countries/argentina.py:76
+#: holidays/countries/argentina.py:211
 msgid "Día del Veterano y de los Caidos en la Guerra de Malvinas"
 msgstr "Veterans Day and the Fallen in the Malvinas War"
 
-#. Labor Day
-#: holidays/countries/argentina.py:81
+#: holidays/countries/argentina.py:219
+msgid "Viernes Santo"
+msgstr "Good Friday"
+
+#: holidays/countries/argentina.py:226
 msgid "Día del Trabajo"
 msgstr "Labor Day"
 
-#. May Revolution Day
-#: holidays/countries/argentina.py:88
+#: holidays/countries/argentina.py:233
 msgid "Día de la Revolución de Mayo"
 msgstr "May Revolution Day"
 
-#. Day Pass to the Immortality of General Martín Miguel de Güemes.
-#: holidays/countries/argentina.py:95
-msgid "Día Pase a la Inmortalidad del General Martín Miguel de Güemes"
-msgstr "Day Pass to the Immortality of General Martín Miguel de Güemes"
+#: holidays/countries/argentina.py:244
+msgid ""
+"Día de los Derechos Argentinos sobre las Islas Malvinas, Sandwich y del "
+"Atlántico Sur"
+msgstr ""
+"Day of Argentine Sovereignty over the Malvinas, Sandwich and South Atlantic "
+"Islands"
 
-#. Day Pass to the Immortality of General D. Manuel Belgrano.
-#: holidays/countries/argentina.py:104
-msgid "Día Pase a la Inmortalidad del General D. Manuel Belgrano"
-msgstr "Day Pass to the Immortality of General D. Manuel Belgrano"
+#: holidays/countries/argentina.py:261
+msgid "Paso a la Inmortalidad del General Don Manuel Belgrano"
+msgstr "Pass to the Immortality of General Don Manuel Belgrano"
 
-#. Independence Day
-#: holidays/countries/argentina.py:113
+#: holidays/countries/argentina.py:270
 msgid "Día de la Independencia"
 msgstr "Independence Day"
 
-#. Day Pass to the Immortality of General D. José de San Martin
-#: holidays/countries/argentina.py:120
-msgid "Día Pase a la Inmortalidad del General D. José de San Martin"
-msgstr "Day Pass to the Immortality of General D. José de San Martin"
+#: holidays/countries/argentina.py:275
+msgid "Inmaculada Concepción de María"
+msgstr "Immaculate Conception"
 
-#: holidays/countries/argentina.py:132
-msgid "Día de la Raza"
-msgstr "Columbus day"
+#: holidays/countries/argentina.py:280
+msgid "Navidad"
+msgstr "Christmas"
 
-#: holidays/countries/argentina.py:134
+#: holidays/countries/argentina.py:290
+msgid "Paso a la Inmortalidad del General Don Martín Miguel de Güemes"
+msgstr "Pass to the Immortality of General Don Martín Miguel de Güemes"
+
+#: holidays/countries/argentina.py:307
+msgid "Paso a la Inmortalidad del General Don José de San Martin"
+msgstr "Pass to the Immortality of General Don José de San Martin"
+
+#: holidays/countries/argentina.py:327
 msgid "Día del Respeto a la Diversidad Cultural"
 msgstr "Respect for Cultural Diversity Day"
 
-#. National Sovereignty Day
-#: holidays/countries/argentina.py:138
-msgid "Día Nacional de la Soberanía"
-msgstr "National Sovereignty Day"
-
-#: holidays/countries/argentina.py:148
-msgid "La Inmaculada Concepción"
-msgstr "Immaculate Conception"
+#: holidays/countries/argentina.py:329
+msgid "Día de la Raza"
+msgstr "Columbus day"
 
-#. Christmas
-#: holidays/countries/argentina.py:151
-msgid "Navidad"
-msgstr "Christmas"
+#: holidays/countries/argentina.py:340
+msgid "Día de la Soberanía Nacional"
+msgstr "National Sovereignty Day"
diff --git a/holidays/locale/en_US/LC_MESSAGES/CL.po b/holidays/locale/en_US/LC_MESSAGES/CL.po
new file mode 100644
index 000000000..1e1a5e2a3
--- /dev/null
+++ b/holidays/locale/en_US/LC_MESSAGES/CL.po
@@ -0,0 +1,133 @@
+# Chile holidays en_US localization.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.21\n"
+"POT-Creation-Date: 2023-02-28 16:42+0200\n"
+"PO-Revision-Date: 2023-02-28 16:46+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: en_US\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+"Generated-By: pygettext.py 1.5\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/chile.py:36 holidays/countries/chile.py:80
+msgid "Feriado nacional"
+msgstr "National Holiday"
+
+#. New Year's Day (Law 2.977)
+#: holidays/countries/chile.py:77
+msgid "Año Nuevo"
+msgstr "New Year's Day"
+
+#: holidays/countries/chile.py:84
+msgid "Viernes Santo"
+msgstr "Good Friday"
+
+#: holidays/countries/chile.py:85
+msgid "Sábado Santo"
+msgstr "Holy Saturday"
+
+#: holidays/countries/chile.py:89
+msgid "Ascensión del Señor"
+msgstr "Ascension of Jesus"
+
+#: holidays/countries/chile.py:95
+msgid "Corpus Christi"
+msgstr "Corpus Christi"
+
+#: holidays/countries/chile.py:99
+msgid "Día Nacional del Trabajo"
+msgstr "Labour Day"
+
+#. Naval Glories Day (Law 2.977)
+#: holidays/countries/chile.py:102
+msgid "Día de las Glorias Navales"
+msgstr "Navy Day"
+
+#. National Day of Indigenous Peoples
+#: holidays/countries/chile.py:105
+msgid "Día Nacional de los Pueblos Indígenas"
+msgstr "National Day of Indigenous Peoples"
+
+#: holidays/countries/chile.py:121
+msgid "San Pedro y San Pablo"
+msgstr "Saint Peter and Saint Paul"
+
+#: holidays/countries/chile.py:127
+msgid "Virgen del Carmen"
+msgstr "Our Lady of Mount Carmel"
+
+#. Day of Assumption of the Virgin (Law 2.977)
+#: holidays/countries/chile.py:130
+msgid "Asunción de la Virgen"
+msgstr "Assumption of Mary"
+
+#: holidays/countries/chile.py:134
+msgid "Día de la Liberación Nacional"
+msgstr "Day of National Liberation"
+
+#: holidays/countries/chile.py:139
+msgid "Día de la Unidad Nacional"
+msgstr "Day of National Unity"
+
+#: holidays/countries/chile.py:146 holidays/countries/chile.py:150
+#: holidays/countries/chile.py:160 holidays/countries/chile.py:164
+msgid "Fiestas Patrias"
+msgstr "National Holiday"
+
+#. Independence Day (Law 2.977)
+#: holidays/countries/chile.py:153
+msgid "Día de la Independencia"
+msgstr "Independence Day"
+
+#. Day of Glories of the Army of Chile (Law 2.977)
+#: holidays/countries/chile.py:156
+msgid "Día de las Glorias del Ejército"
+msgstr "Army Day"
+
+#: holidays/countries/chile.py:169
+msgid "Día del Encuentro de dos Mundos"
+msgstr "Meeting of Two Worlds' Day"
+
+#: holidays/countries/chile.py:171
+msgid "Día de la Raza"
+msgstr "Columbus Day"
+
+#: holidays/countries/chile.py:184
+msgid "Día Nacional de las Iglesias Evangélicas y Protestantes"
+msgstr "Reformation Day"
+
+#. All Saints Day (Law 2.977)
+#: holidays/countries/chile.py:189
+msgid "Día de Todos los Santos"
+msgstr "All Saints' Day"
+
+#. Immaculate Conception (Law 2.977)
+#: holidays/countries/chile.py:192
+msgid "La Inmaculada Concepción"
+msgstr "Immaculate Conception"
+
+#: holidays/countries/chile.py:195
+msgid "Víspera de Navidad"
+msgstr "Christmas Eve"
+
+#. Christmas (Law 2.977)
+#: holidays/countries/chile.py:198
+msgid "Navidad"
+msgstr "Christmas"
+
+#. Law 20.663
+#: holidays/countries/chile.py:203
+msgid "Asalto y Toma del Morro de Arica"
+msgstr "Assault and Capture of Cape Arica"
+
+#. Law 20.678
+#: holidays/countries/chile.py:210
+msgid "Nacimiento del Prócer de la Independencia (Chillán y Chillán Viejo)"
+msgstr "Nativity of Bernardo O'Higgins (Chillán and Chillán Viejo communes)"
diff --git a/holidays/locale/en_US/LC_MESSAGES/CO.po b/holidays/locale/en_US/LC_MESSAGES/CO.po
new file mode 100644
index 000000000..f04367211
--- /dev/null
+++ b/holidays/locale/en_US/LC_MESSAGES/CO.po
@@ -0,0 +1,102 @@
+# Colombia holidays en_US localization.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-19 17:09+0200\n"
+"PO-Revision-Date: 2023-02-19 20:15+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: en_US\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/colombia.py:52
+#, c-format
+msgid "%s (Observado)"
+msgstr "%s (Observed)"
+
+#. New Year's Day
+#: holidays/countries/colombia.py:60
+msgid "Año Nuevo"
+msgstr "New Year's Day"
+
+#: holidays/countries/colombia.py:66
+msgid "Día de los Reyes Magos"
+msgstr "Epiphany"
+
+#: holidays/countries/colombia.py:72
+msgid "Día de San José"
+msgstr "Saint Joseph's Day"
+
+#. Labor Day
+#: holidays/countries/colombia.py:76
+msgid "Día del Trabajo"
+msgstr "Labour Day"
+
+#: holidays/countries/colombia.py:82
+msgid "San Pedro y San Pablo"
+msgstr "Saint Peter and Saint Paul"
+
+#. Independence Day
+#: holidays/countries/colombia.py:86
+msgid "Día de la Independencia"
+msgstr "Independence Day"
+
+#. Battle of Boyaca
+#: holidays/countries/colombia.py:89
+msgid "Batalla de Boyacá"
+msgstr "Battle of Boyacá"
+
+#: holidays/countries/colombia.py:95
+msgid "La Asunción"
+msgstr "Assumption of Mary"
+
+#: holidays/countries/colombia.py:101
+msgid "Día de la Raza"
+msgstr "Columbus Day"
+
+#: holidays/countries/colombia.py:108
+msgid "Día de Todos los Santos"
+msgstr "All Saints' Day"
+
+#: holidays/countries/colombia.py:114
+msgid "Independencia de Cartagena"
+msgstr "Independence of Cartagena"
+
+#. Immaculate Conception
+#: holidays/countries/colombia.py:119
+msgid "La Inmaculada Concepción"
+msgstr "Immaculate Conception"
+
+#. Christmas
+#: holidays/countries/colombia.py:122
+msgid "Navidad"
+msgstr "Christmas"
+
+#. Maundy Thursday
+#: holidays/countries/colombia.py:128
+msgid "Jueves Santo"
+msgstr "Maundy Thursday"
+
+#. Good Friday
+#: holidays/countries/colombia.py:131
+msgid "Viernes Santo"
+msgstr "Good Friday"
+
+#: holidays/countries/colombia.py:136
+msgid "Ascensión del señor"
+msgstr "Ascension of Jesus"
+
+#: holidays/countries/colombia.py:142
+msgid "Corpus Christi"
+msgstr "Corpus Christi"
+
+#: holidays/countries/colombia.py:149
+msgid "Sagrado Corazón"
+msgstr "Sacred Heart"
diff --git a/holidays/locale/en_US/LC_MESSAGES/JP.po b/holidays/locale/en_US/LC_MESSAGES/JP.po
index dd43ea735..0246a1971 100644
--- a/holidays/locale/en_US/LC_MESSAGES/JP.po
+++ b/holidays/locale/en_US/LC_MESSAGES/JP.po
@@ -3,10 +3,10 @@
 #
 msgid ""
 msgstr ""
-"Project-Id-Version: PACKAGE 1.0\n"
+"Project-Id-Version: Python Holidays 0.20\n"
 "POT-Creation-Date: 2023-02-15 08:36-0800\n"
-"PO-Revision-Date: 2023-02-14 19:19-0800\n"
-"Last-Translator: Arkadii Yakovets <ark@cho.red>\n"
+"PO-Revision-Date: 2023-02-19 12:31+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
 "Language-Team: Python Holidays localization team\n"
 "Language: en_US\n"
 "MIME-Version: 1.0\n"
@@ -101,7 +101,7 @@ msgstr "Autumnal Equinox"
 
 #: holidays/countries/japan.py:130 holidays/countries/japan.py:132
 msgid "体育の日"
-msgstr "Sports Day"
+msgstr "Physical Education Day"
 
 #: holidays/countries/japan.py:134 holidays/countries/japan.py:136
 #: holidays/countries/japan.py:138
diff --git a/holidays/locale/en_US/LC_MESSAGES/MC.po b/holidays/locale/en_US/LC_MESSAGES/MC.po
new file mode 100644
index 000000000..036ed3b49
--- /dev/null
+++ b/holidays/locale/en_US/LC_MESSAGES/MC.po
@@ -0,0 +1,86 @@
+# Monaco holidays en_US localization.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-20 11:58+0200\n"
+"PO-Revision-Date: 2023-02-20 12:13+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: en_US\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/monaco.py:31
+msgid "Jour férié"
+msgstr "Public holiday"
+
+#: holidays/countries/monaco.py:39
+#, c-format
+msgid "%s (Observé)"
+msgstr "%s (Observed)"
+
+#. New Year's Day
+#: holidays/countries/monaco.py:45
+msgid "Le jour de l'An"
+msgstr "New Year's Day"
+
+#. Saint Dévote's Day
+#: holidays/countries/monaco.py:48
+msgid "La Sainte Dévote"
+msgstr "Saint Dévote's Day"
+
+#. Easter Monday
+#: holidays/countries/monaco.py:53
+msgid "Le lundi de Pâques"
+msgstr "Easter Monday"
+
+#. Labour Day
+#: holidays/countries/monaco.py:56
+msgid "Fête de la Travaille"
+msgstr "Labour Day"
+
+#. Ascension's Day
+#: holidays/countries/monaco.py:59
+msgid "L'Ascension"
+msgstr "Ascension's Day"
+
+#. Whit Monday
+#: holidays/countries/monaco.py:62
+msgid "Le lundi de Pentecôte"
+msgstr "Whit Monday"
+
+#. Corpus Christi
+#: holidays/countries/monaco.py:65
+msgid "La Fête Dieu"
+msgstr "Corpus Christi"
+
+#. Assumption's Day
+#: holidays/countries/monaco.py:70
+msgid "L'Assomption de Marie"
+msgstr "Assumption's Day"
+
+#. All Saints' Day
+#: holidays/countries/monaco.py:74
+msgid "La Toussaint"
+msgstr "All Saints' Day"
+
+#. Prince's Day
+#: holidays/countries/monaco.py:77
+msgid "La Fête du Prince"
+msgstr "Prince's Day"
+
+#. Immaculate Conception's Day
+#: holidays/countries/monaco.py:83
+msgid "L'Immaculée Conception"
+msgstr "Immaculate Conception's Day"
+
+#. Christmas Day
+#: holidays/countries/monaco.py:86
+msgid "Noël"
+msgstr "Christmas Day"
diff --git a/holidays/locale/en_US/LC_MESSAGES/PE.po b/holidays/locale/en_US/LC_MESSAGES/PE.po
new file mode 100644
index 000000000..b86de0f41
--- /dev/null
+++ b/holidays/locale/en_US/LC_MESSAGES/PE.po
@@ -0,0 +1,92 @@
+# Peru holidays en_US localization.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-21 15:18+0200\n"
+"PO-Revision-Date: 2023-02-21 15:19+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: en_US\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#. New Year's Day
+#: holidays/countries/peru.py:34
+msgid "Año Nuevo"
+msgstr "New Year's Day"
+
+#. Holy Thursday
+#: holidays/countries/peru.py:38
+msgid "Jueves Santo"
+msgstr "Maundy Thursday"
+
+#. Good Friday
+#: holidays/countries/peru.py:41
+msgid "Viernes Santo"
+msgstr "Good Friday"
+
+#. Easter Sunday
+#: holidays/countries/peru.py:44
+msgid "Domingo de Resurrección"
+msgstr "Easter Sunday"
+
+#. Labor Day
+#: holidays/countries/peru.py:47
+msgid "Día del Trabajo"
+msgstr "Labour Day"
+
+#. Feast of Saints Peter and Paul
+#: holidays/countries/peru.py:50
+msgid "San Pedro y San Pablo"
+msgstr "Saint Peter and Saint Paul"
+
+#. Independence Day
+#: holidays/countries/peru.py:53
+msgid "Día de la Independencia"
+msgstr "Independence Day"
+
+#. Great Military Parade Day
+#: holidays/countries/peru.py:56
+msgid "Día de la Gran Parada Militar"
+msgstr "Great Military Parade Day"
+
+#. Battle of Junín
+#: holidays/countries/peru.py:60
+msgid "Batalla de Junín"
+msgstr "Battle of Junín Day"
+
+#. Santa Rosa de Lima
+#: holidays/countries/peru.py:63
+msgid "Santa Rosa de Lima"
+msgstr "Rose of Lima Day"
+
+#. Battle of Angamos
+#: holidays/countries/peru.py:66
+msgid "Combate de Angamos"
+msgstr "Battle of Angamos Day"
+
+#. All Saints Day
+#: holidays/countries/peru.py:69
+msgid "Todos Los Santos"
+msgstr "All Saints' Day"
+
+#. Immaculate Conception
+#: holidays/countries/peru.py:72
+msgid "Inmaculada Concepción"
+msgstr "Immaculate Conception Day"
+
+#. Battle of Ayacucho
+#: holidays/countries/peru.py:76
+msgid "Batalla de Ayacucho"
+msgstr "Battle of Ayacucho Day"
+
+#. Christmas
+#: holidays/countries/peru.py:79
+msgid "Navidad del Señor"
+msgstr "Christmas Day"
diff --git a/holidays/locale/en_US/LC_MESSAGES/TH.po b/holidays/locale/en_US/LC_MESSAGES/TH.po
new file mode 100644
index 000000000..f753301f1
--- /dev/null
+++ b/holidays/locale/en_US/LC_MESSAGES/TH.po
@@ -0,0 +1,173 @@
+# Thailand holidays en_US localization.
+# Authors: PPsyrius <ppsyrius@ppsyrius.dev>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-03-02 00:37+0700\n"
+"PO-Revision-Date: \n"
+"Last-Translator: PPsyrius <ppsyrius@ppsyrius.dev>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: en_US\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/thailand.py:119
+msgid "วันหยุดชดเชย"
+msgstr "Special In Lieu Holiday"
+
+#: holidays/countries/thailand.py:120
+msgid "วันเลือกตั้ง"
+msgstr "Thai Election Day"
+
+#: holidays/countries/thailand.py:121 holidays/countries/thailand.py:145
+#: holidays/countries/thailand.py:286 holidays/countries/thailand.py:309
+#: holidays/countries/thailand.py:366 holidays/countries/thailand.py:632
+#: holidays/countries/thailand.py:636
+#, c-format
+msgid "ชดเชย%s"
+msgstr "%s (in lieu)"
+
+#: holidays/countries/thailand.py:122
+msgid "วันหยุดพิเศษ (เพิ่มเติม)"
+msgstr "Bridge Public Holiday"
+
+#: holidays/countries/thailand.py:126
+msgid "พระราชพิธีกาญจนาภิเษก พ.ศ. 2539"
+msgstr "HM King Bhumibol Adulyadej's Golden Jubilee"
+
+#: holidays/countries/thailand.py:127
+msgid "พระราชพิธีฉลองสิริราชสมบัติครบ 60 ปี พ.ศ. 2549"
+msgstr "HM King Bhumibol Adulyadej's 60th Anniversary of Accession Event"
+
+#: holidays/countries/thailand.py:130
+msgid "วันหยุดพิเศษ (คมช.)"
+msgstr "Emergency Lockdown (Thai Military Coup d'état)"
+
+#: holidays/countries/thailand.py:131
+msgid "วันหยุดพิเศษ (การเมือง)"
+msgstr "Emergency Lockdown (Thai Political Unrest)"
+
+#: holidays/countries/thailand.py:132
+msgid "วันหยุดพิเศษ (มหาอุทกภัย พ.ศ. 2554)"
+msgstr "Emergency Lockdown (2011 Thailand Floods)"
+
+#: holidays/countries/thailand.py:135
+msgid "วันหยุดพิเศษ (ร่วมถวายอาลัย ส่งดวงพระวิญญาณพระบรมศพ)"
+msgstr "Day of Mourning for HM King Bhumibol Adulyadej"
+
+#: holidays/countries/thailand.py:138
+msgid "วันพระราชพิธีถวายพระเพลิงพระบรมศพพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช"
+msgstr "HM King Bhumibol Adulyadej's Royal Cremation Ceremony"
+
+#: holidays/countries/thailand.py:142
+msgid "พระราชพิธีบรมราชาภิเษก พระบาทสมเด็จพระวชิรเกล้าเจ้าอยู่หัว"
+msgstr "HM King Maha Vajiralongkorn's Coronation Celebrations"
+
+#: holidays/countries/thailand.py:145 holidays/countries/thailand.py:339
+msgid "วันสงกรานต์"
+msgstr "Songkran Festival"
+
+#: holidays/countries/thailand.py:298
+msgid "วันขึ้นปีใหม่"
+msgstr "New Year's Day"
+
+#: holidays/countries/thailand.py:309 holidays/countries/thailand.py:573
+msgid "วันสิ้นปี"
+msgstr "New Year's Eve"
+
+#: holidays/countries/thailand.py:323
+msgid "วันจักรี"
+msgstr "Chakri Memorial Day"
+
+#: holidays/countries/thailand.py:388
+msgid "วันแรงงานแห่งชาติ"
+msgstr "National Labour Day"
+
+#: holidays/countries/thailand.py:400
+msgid "วันชาติ"
+msgstr "National Day"
+
+#: holidays/countries/thailand.py:409
+msgid "วันฉัตรมงคล"
+msgstr "Coronation Day"
+
+#: holidays/countries/thailand.py:424
+msgid "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสุทิดา พัชรสุธาพิมลลักษณ พระบรมราชินี"
+msgstr "HM Queen Suthida's Birthday"
+
+#: holidays/countries/thailand.py:438
+msgid ""
+"วันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรเมนทรรามาธิบดีศรีสินทรมหาวชิราลงกรณ "
+"พระวชิรเกล้าเจ้าอยู่หัว"
+msgstr "HM King Maha Vajiralongkorn's Birthday"
+
+#: holidays/countries/thailand.py:456
+msgid "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสิริกิติ์ พระบรมราชินีนาถ"
+msgstr "HM Queen Sirikit's Birthday"
+
+#: holidays/countries/thailand.py:464
+msgid "วันเฉลิมพระชนมพรรษาสมเด็จพระบรมราชชนนีพันปีหลวง"
+msgstr "HM Queen Sirikit The Queen Mother's Birthday"
+
+#: holidays/countries/thailand.py:475
+msgid "วันแม่แห่งชาติ"
+msgstr "National Mother's Day"
+
+#: holidays/countries/thailand.py:491
+msgid "วันคล้ายวันสวรรคตพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+msgstr "HM King Bhumibol Adulyadej Memorial Day"
+
+#: holidays/countries/thailand.py:499
+msgid ""
+"วันคล้ายวันสวรรคตพระบาทสมเด็จพระบรมชนกาธิเบศร มหาภูมิพลอดุลยเดชมหาราช บรมนาถบพิตร"
+msgstr "HM King Bhumibol Adulyadej the Great Memorial Day"
+
+#: holidays/countries/thailand.py:511
+msgid "วันปิยมหาราช"
+msgstr "HM King Chulalongkorn Memorial Day"
+
+#: holidays/countries/thailand.py:524
+#, fuzzy
+msgid "วันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+msgstr "HM King Bhumibol Adulyadej's Birthday"
+
+#: holidays/countries/thailand.py:532
+msgid "วันคล้ายวันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+msgstr "HM King Bhumibol Adulyadej's Birthday"
+
+#: holidays/countries/thailand.py:540
+msgid ""
+"วันคล้ายวันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระบรมชนกาธิเบศร มหาภูมิพลอดุลยเดชมหาราช "
+"บรมนาถบพิตร"
+msgstr "HM King Bhumibol Adulyadej the Great's Birthday"
+
+#: holidays/countries/thailand.py:554
+msgid "วันพ่อแห่งชาติ"
+msgstr "National Father's Day"
+
+#: holidays/countries/thailand.py:563
+msgid "วันรัฐธรรมนูญ"
+msgstr "Constitution Day"
+
+#: holidays/countries/thailand.py:589
+msgid "วันมาฆบูชา"
+msgstr "Makha Bucha"
+
+#: holidays/countries/thailand.py:597
+msgid "วันวิสาขบูชา"
+msgstr "Visakha Bucha"
+
+#: holidays/countries/thailand.py:606 holidays/countries/thailand.py:638
+msgid "วันอาสาฬหบูชา"
+msgstr "Asarnha Bucha"
+
+#: holidays/countries/thailand.py:615 holidays/countries/thailand.py:634
+msgid "วันเข้าพรรษา"
+msgstr "Buddhist Lent Day"
+
+#: holidays/countries/thailand.py:652
+msgid "วันพืชมงคล"
+msgstr "Royal Ploughing Ceremony"
diff --git a/holidays/locale/es/LC_MESSAGES/AR.po b/holidays/locale/es/LC_MESSAGES/AR.po
index 70786e5d2..14bcae9c5 100644
--- a/holidays/locale/es/LC_MESSAGES/AR.po
+++ b/holidays/locale/es/LC_MESSAGES/AR.po
@@ -4,96 +4,119 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: Python Holidays 0.20\n"
-"POT-Creation-Date: 2023-02-15 08:13-0800\n"
-"PO-Revision-Date: 2023-02-16 08:55-0800\n"
-"Last-Translator: Arkadii Yakovets <ark@cho.red>\n"
+"POT-Creation-Date: 2023-03-02 00:39+0700\n"
+"PO-Revision-Date: 2023-02-20 19:02+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
 "Language-Team: Python Holidays localization team\n"
 "Language: es\n"
 "MIME-Version: 1.0\n"
 "Content-Type: text/plain; charset=UTF-8\n"
 "Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
 "Generated-By: Lingua 4.15.0\n"
 "X-Generator: Poedit 3.2.2\n"
 
-#: holidays/countries/argentina.py:41
-msgid "Año Nuevo"
+#: holidays/countries/argentina.py:71
+msgid "Feriado con fines turísticos"
 msgstr ""
 
-#. Carnival days
-#: holidays/countries/argentina.py:45
-msgid "Día de Carnaval"
+#: holidays/countries/argentina.py:75
+msgid "Bicentenario de la creación y primera jura de la bandera nacional"
 msgstr ""
 
-#. Memory's National Day for the Truth and Justice
-#: holidays/countries/argentina.py:50
-msgid "Día Nacional de la Memoria por la Verdad y la Justicia"
+#: holidays/countries/argentina.py:78
+msgid "Bicentenario de la Batalla de Tucumán"
+msgstr ""
+
+#: holidays/countries/argentina.py:79
+msgid ""
+"Bicentenario de la sesión inaugural de la Asamblea Nacional Constituyente "
+"del año 1813"
+msgstr ""
+
+#: holidays/countries/argentina.py:83
+msgid "Bicentenario de la Batalla de Salta"
+msgstr ""
+
+#: holidays/countries/argentina.py:84
+msgid "Censo nacional 2022"
+msgstr ""
+
+#: holidays/countries/argentina.py:162 holidays/countries/argentina.py:165
+#, c-format
+msgid "%s (Observado)"
+msgstr ""
+
+#: holidays/countries/argentina.py:177
+msgid "Año Nuevo"
 msgstr ""
 
-#. Holy Week
-#: holidays/countries/argentina.py:60
-msgid "Semana Santa (Jueves Santo)"
+#: holidays/countries/argentina.py:185
+msgid "Día de Carnaval"
 msgstr ""
 
-#: holidays/countries/argentina.py:61
-msgid "Semana Santa (Viernes Santo)"
+#: holidays/countries/argentina.py:194
+msgid "Día Nacional de la Memoria por la Verdad y la Justicia"
 msgstr ""
 
-#: holidays/countries/argentina.py:62
-msgid "Día de Pascuas"
+#: holidays/countries/argentina.py:209
+msgid "Día del Veterano de Guerra"
 msgstr ""
 
-#: holidays/countries/argentina.py:76
+#: holidays/countries/argentina.py:211
 msgid "Día del Veterano y de los Caidos en la Guerra de Malvinas"
 msgstr ""
 
-#. Labor Day
-#: holidays/countries/argentina.py:81
+#: holidays/countries/argentina.py:219
+msgid "Viernes Santo"
+msgstr ""
+
+#: holidays/countries/argentina.py:226
 msgid "Día del Trabajo"
 msgstr ""
 
-#. May Revolution Day
-#: holidays/countries/argentina.py:88
+#: holidays/countries/argentina.py:233
 msgid "Día de la Revolución de Mayo"
 msgstr ""
 
-#. Day Pass to the Immortality of General Martín Miguel de Güemes.
-#: holidays/countries/argentina.py:95
-msgid "Día Pase a la Inmortalidad del General Martín Miguel de Güemes"
+#: holidays/countries/argentina.py:244
+msgid ""
+"Día de los Derechos Argentinos sobre las Islas Malvinas, Sandwich y del "
+"Atlántico Sur"
 msgstr ""
 
-#. Day Pass to the Immortality of General D. Manuel Belgrano.
-#: holidays/countries/argentina.py:104
-msgid "Día Pase a la Inmortalidad del General D. Manuel Belgrano"
+#: holidays/countries/argentina.py:261
+msgid "Paso a la Inmortalidad del General Don Manuel Belgrano"
 msgstr ""
 
-#. Independence Day
-#: holidays/countries/argentina.py:113
+#: holidays/countries/argentina.py:270
 msgid "Día de la Independencia"
 msgstr ""
 
-#. Day Pass to the Immortality of General D. José de San Martin
-#: holidays/countries/argentina.py:120
-msgid "Día Pase a la Inmortalidad del General D. José de San Martin"
+#: holidays/countries/argentina.py:275
+msgid "Inmaculada Concepción de María"
 msgstr ""
 
-#: holidays/countries/argentina.py:132
-msgid "Día de la Raza"
+#: holidays/countries/argentina.py:280
+msgid "Navidad"
 msgstr ""
 
-#: holidays/countries/argentina.py:134
-msgid "Día del Respeto a la Diversidad Cultural"
+#: holidays/countries/argentina.py:290
+msgid "Paso a la Inmortalidad del General Don Martín Miguel de Güemes"
 msgstr ""
 
-#. National Sovereignty Day
-#: holidays/countries/argentina.py:138
-msgid "Día Nacional de la Soberanía"
+#: holidays/countries/argentina.py:307
+msgid "Paso a la Inmortalidad del General Don José de San Martin"
 msgstr ""
 
-#: holidays/countries/argentina.py:148
-msgid "La Inmaculada Concepción"
+#: holidays/countries/argentina.py:327
+msgid "Día del Respeto a la Diversidad Cultural"
 msgstr ""
 
-#. Christmas
-#: holidays/countries/argentina.py:151
-msgid "Navidad"
+#: holidays/countries/argentina.py:329
+msgid "Día de la Raza"
+msgstr ""
+
+#: holidays/countries/argentina.py:340
+msgid "Día de la Soberanía Nacional"
 msgstr ""
diff --git a/holidays/locale/es/LC_MESSAGES/CL.po b/holidays/locale/es/LC_MESSAGES/CL.po
new file mode 100644
index 000000000..2e66bf224
--- /dev/null
+++ b/holidays/locale/es/LC_MESSAGES/CL.po
@@ -0,0 +1,133 @@
+# Chile holidays.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.21\n"
+"POT-Creation-Date: 2023-02-28 16:42+0200\n"
+"PO-Revision-Date: 2023-02-28 16:43+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: es\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+"Generated-By: pygettext.py 1.5\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/chile.py:36 holidays/countries/chile.py:80
+msgid "Feriado nacional"
+msgstr ""
+
+#. New Year's Day (Law 2.977)
+#: holidays/countries/chile.py:77
+msgid "Año Nuevo"
+msgstr ""
+
+#: holidays/countries/chile.py:84
+msgid "Viernes Santo"
+msgstr ""
+
+#: holidays/countries/chile.py:85
+msgid "Sábado Santo"
+msgstr ""
+
+#: holidays/countries/chile.py:89
+msgid "Ascensión del Señor"
+msgstr ""
+
+#: holidays/countries/chile.py:95
+msgid "Corpus Christi"
+msgstr ""
+
+#: holidays/countries/chile.py:99
+msgid "Día Nacional del Trabajo"
+msgstr ""
+
+#. Naval Glories Day (Law 2.977)
+#: holidays/countries/chile.py:102
+msgid "Día de las Glorias Navales"
+msgstr ""
+
+#. National Day of Indigenous Peoples
+#: holidays/countries/chile.py:105
+msgid "Día Nacional de los Pueblos Indígenas"
+msgstr ""
+
+#: holidays/countries/chile.py:121
+msgid "San Pedro y San Pablo"
+msgstr ""
+
+#: holidays/countries/chile.py:127
+msgid "Virgen del Carmen"
+msgstr ""
+
+#. Day of Assumption of the Virgin (Law 2.977)
+#: holidays/countries/chile.py:130
+msgid "Asunción de la Virgen"
+msgstr ""
+
+#: holidays/countries/chile.py:134
+msgid "Día de la Liberación Nacional"
+msgstr ""
+
+#: holidays/countries/chile.py:139
+msgid "Día de la Unidad Nacional"
+msgstr ""
+
+#: holidays/countries/chile.py:146 holidays/countries/chile.py:150
+#: holidays/countries/chile.py:160 holidays/countries/chile.py:164
+msgid "Fiestas Patrias"
+msgstr ""
+
+#. Independence Day (Law 2.977)
+#: holidays/countries/chile.py:153
+msgid "Día de la Independencia"
+msgstr ""
+
+#. Day of Glories of the Army of Chile (Law 2.977)
+#: holidays/countries/chile.py:156
+msgid "Día de las Glorias del Ejército"
+msgstr ""
+
+#: holidays/countries/chile.py:169
+msgid "Día del Encuentro de dos Mundos"
+msgstr ""
+
+#: holidays/countries/chile.py:171
+msgid "Día de la Raza"
+msgstr ""
+
+#: holidays/countries/chile.py:184
+msgid "Día Nacional de las Iglesias Evangélicas y Protestantes"
+msgstr ""
+
+#. All Saints Day (Law 2.977)
+#: holidays/countries/chile.py:189
+msgid "Día de Todos los Santos"
+msgstr ""
+
+#. Immaculate Conception (Law 2.977)
+#: holidays/countries/chile.py:192
+msgid "La Inmaculada Concepción"
+msgstr ""
+
+#: holidays/countries/chile.py:195
+msgid "Víspera de Navidad"
+msgstr ""
+
+#. Christmas (Law 2.977)
+#: holidays/countries/chile.py:198
+msgid "Navidad"
+msgstr ""
+
+#. Law 20.663
+#: holidays/countries/chile.py:203
+msgid "Asalto y Toma del Morro de Arica"
+msgstr ""
+
+#. Law 20.678
+#: holidays/countries/chile.py:210
+msgid "Nacimiento del Prócer de la Independencia (Chillán y Chillán Viejo)"
+msgstr ""
diff --git a/holidays/locale/es/LC_MESSAGES/CO.po b/holidays/locale/es/LC_MESSAGES/CO.po
new file mode 100644
index 000000000..fe5242211
--- /dev/null
+++ b/holidays/locale/es/LC_MESSAGES/CO.po
@@ -0,0 +1,102 @@
+# Colombia holidays.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-19 17:09+0200\n"
+"PO-Revision-Date: 2023-02-19 17:16+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: es\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/colombia.py:52
+#, c-format
+msgid "%s (Observado)"
+msgstr ""
+
+#. New Year's Day
+#: holidays/countries/colombia.py:60
+msgid "Año Nuevo"
+msgstr ""
+
+#: holidays/countries/colombia.py:66
+msgid "Día de los Reyes Magos"
+msgstr ""
+
+#: holidays/countries/colombia.py:72
+msgid "Día de San José"
+msgstr ""
+
+#. Labor Day
+#: holidays/countries/colombia.py:76
+msgid "Día del Trabajo"
+msgstr ""
+
+#: holidays/countries/colombia.py:82
+msgid "San Pedro y San Pablo"
+msgstr ""
+
+#. Independence Day
+#: holidays/countries/colombia.py:86
+msgid "Día de la Independencia"
+msgstr ""
+
+#. Battle of Boyaca
+#: holidays/countries/colombia.py:89
+msgid "Batalla de Boyacá"
+msgstr ""
+
+#: holidays/countries/colombia.py:95
+msgid "La Asunción"
+msgstr ""
+
+#: holidays/countries/colombia.py:101
+msgid "Día de la Raza"
+msgstr ""
+
+#: holidays/countries/colombia.py:108
+msgid "Día de Todos los Santos"
+msgstr ""
+
+#: holidays/countries/colombia.py:114
+msgid "Independencia de Cartagena"
+msgstr ""
+
+#. Immaculate Conception
+#: holidays/countries/colombia.py:119
+msgid "La Inmaculada Concepción"
+msgstr ""
+
+#. Christmas
+#: holidays/countries/colombia.py:122
+msgid "Navidad"
+msgstr ""
+
+#. Maundy Thursday
+#: holidays/countries/colombia.py:128
+msgid "Jueves Santo"
+msgstr ""
+
+#. Good Friday
+#: holidays/countries/colombia.py:131
+msgid "Viernes Santo"
+msgstr ""
+
+#: holidays/countries/colombia.py:136
+msgid "Ascensión del señor"
+msgstr ""
+
+#: holidays/countries/colombia.py:142
+msgid "Corpus Christi"
+msgstr ""
+
+#: holidays/countries/colombia.py:149
+msgid "Sagrado Corazón"
+msgstr ""
diff --git a/holidays/locale/es/LC_MESSAGES/PE.po b/holidays/locale/es/LC_MESSAGES/PE.po
new file mode 100644
index 000000000..4b1834657
--- /dev/null
+++ b/holidays/locale/es/LC_MESSAGES/PE.po
@@ -0,0 +1,92 @@
+# Peru holidays.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-21 15:18+0200\n"
+"PO-Revision-Date: 2023-02-21 15:18+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: es\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#. New Year's Day
+#: holidays/countries/peru.py:34
+msgid "Año Nuevo"
+msgstr ""
+
+#. Holy Thursday
+#: holidays/countries/peru.py:38
+msgid "Jueves Santo"
+msgstr ""
+
+#. Good Friday
+#: holidays/countries/peru.py:41
+msgid "Viernes Santo"
+msgstr ""
+
+#. Easter Sunday
+#: holidays/countries/peru.py:44
+msgid "Domingo de Resurrección"
+msgstr ""
+
+#. Labor Day
+#: holidays/countries/peru.py:47
+msgid "Día del Trabajo"
+msgstr ""
+
+#. Feast of Saints Peter and Paul
+#: holidays/countries/peru.py:50
+msgid "San Pedro y San Pablo"
+msgstr ""
+
+#. Independence Day
+#: holidays/countries/peru.py:53
+msgid "Día de la Independencia"
+msgstr ""
+
+#. Great Military Parade Day
+#: holidays/countries/peru.py:56
+msgid "Día de la Gran Parada Militar"
+msgstr ""
+
+#. Battle of Junín
+#: holidays/countries/peru.py:60
+msgid "Batalla de Junín"
+msgstr ""
+
+#. Santa Rosa de Lima
+#: holidays/countries/peru.py:63
+msgid "Santa Rosa de Lima"
+msgstr ""
+
+#. Battle of Angamos
+#: holidays/countries/peru.py:66
+msgid "Combate de Angamos"
+msgstr ""
+
+#. All Saints Day
+#: holidays/countries/peru.py:69
+msgid "Todos Los Santos"
+msgstr ""
+
+#. Immaculate Conception
+#: holidays/countries/peru.py:72
+msgid "Inmaculada Concepción"
+msgstr ""
+
+#. Battle of Ayacucho
+#: holidays/countries/peru.py:76
+msgid "Batalla de Ayacucho"
+msgstr ""
+
+#. Christmas
+#: holidays/countries/peru.py:79
+msgid "Navidad del Señor"
+msgstr ""
diff --git a/holidays/locale/fr/LC_MESSAGES/MC.po b/holidays/locale/fr/LC_MESSAGES/MC.po
new file mode 100644
index 000000000..1c48f275f
--- /dev/null
+++ b/holidays/locale/fr/LC_MESSAGES/MC.po
@@ -0,0 +1,86 @@
+# Monaco holidays.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-20 11:58+0200\n"
+"PO-Revision-Date: 2023-02-20 12:00+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: fr\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n > 1);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: ./holidays/countries/monaco.py:31
+msgid "Jour férié"
+msgstr ""
+
+#: ./holidays/countries/monaco.py:39
+#, c-format
+msgid "%s (Observé)"
+msgstr ""
+
+#. New Year's Day
+#: ./holidays/countries/monaco.py:45
+msgid "Le jour de l'An"
+msgstr ""
+
+#. Saint Dévote's Day
+#: ./holidays/countries/monaco.py:48
+msgid "La Sainte Dévote"
+msgstr ""
+
+#. Easter Monday
+#: ./holidays/countries/monaco.py:53
+msgid "Le lundi de Pâques"
+msgstr ""
+
+#. Labour Day
+#: ./holidays/countries/monaco.py:56
+msgid "Fête de la Travaille"
+msgstr ""
+
+#. Ascension's Day
+#: ./holidays/countries/monaco.py:59
+msgid "L'Ascension"
+msgstr ""
+
+#. Whit Monday
+#: ./holidays/countries/monaco.py:62
+msgid "Le lundi de Pentecôte"
+msgstr ""
+
+#. Corpus Christi
+#: ./holidays/countries/monaco.py:65
+msgid "La Fête Dieu"
+msgstr ""
+
+#. Assumption's Day
+#: ./holidays/countries/monaco.py:70
+msgid "L'Assomption de Marie"
+msgstr ""
+
+#. All Saints' Day
+#: ./holidays/countries/monaco.py:74
+msgid "La Toussaint"
+msgstr ""
+
+#. Prince's Day
+#: ./holidays/countries/monaco.py:77
+msgid "La Fête du Prince"
+msgstr ""
+
+#. Immaculate Conception's Day
+#: ./holidays/countries/monaco.py:83
+msgid "L'Immaculée Conception"
+msgstr ""
+
+#. Christmas Day
+#: ./holidays/countries/monaco.py:86
+msgid "Noël"
+msgstr ""
diff --git a/holidays/locale/th/LC_MESSAGES/CA.po b/holidays/locale/th/LC_MESSAGES/CA.po
new file mode 100644
index 000000000..351cd1d60
--- /dev/null
+++ b/holidays/locale/th/LC_MESSAGES/CA.po
@@ -0,0 +1,149 @@
+# Canada holidays th localization.
+# Authors: PPsyrius <ppsyrius@ppsyrius.dev>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.21\n"
+"POT-Creation-Date: 2023-02-24 17:37+0700\n"
+"PO-Revision-Date: 2023-02-24 17:37+0700\n"
+"Last-Translator: PPsyrius <ppsyrius@ppsyrius.dev>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: th\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Generated-By: pygettext.py 1.5\n"
+
+#. New Year's Day.
+#: holidays/countries/canada.py:63
+msgid "New Year's Day"
+msgstr "วันขึ้นปีใหม่"
+
+#: holidays/countries/canada.py:67 holidays/countries/canada.py:168
+#: holidays/countries/canada.py:192 holidays/countries/canada.py:201
+#: holidays/countries/canada.py:280 holidays/countries/canada.py:287
+#: holidays/countries/canada.py:294
+#, c-format
+msgid "%s (Observed)"
+msgstr "ชดเชย%s"
+
+#: holidays/countries/canada.py:78 holidays/countries/canada.py:83
+#: holidays/countries/canada.py:87
+msgid "Family Day"
+msgstr "วันครอบครัว"
+
+#: holidays/countries/canada.py:91
+msgid "Louis Riel Day"
+msgstr "วันหลุยส์เรียล (แมนิโทบา)"
+
+#: holidays/countries/canada.py:95 holidays/countries/canada.py:99
+msgid "Islander Day"
+msgstr "วันชาวเกาะ (พรินซ์เอดเวิร์ดไอแลนด์)"
+
+#. Heritage Day.
+#: holidays/countries/canada.py:105 holidays/countries/canada.py:124
+#: holidays/countries/canada.py:213
+msgid "Heritage Day"
+msgstr "วันมรดก"
+
+#. St. Patrick's Day.
+#: holidays/countries/canada.py:131
+msgid "St. Patrick's Day"
+msgstr "วันเซนต์แพทริก (นิวฟันด์แลนด์และแลบราดอร์)"
+
+#. Good Friday.
+#: holidays/countries/canada.py:135
+msgid "Good Friday"
+msgstr "วันศุกร์ประเสริฐ"
+
+#. Easter Monday.
+#: holidays/countries/canada.py:137
+msgid "Easter Monday"
+msgstr "วันจันทร์อีสเตอร์"
+
+#: holidays/countries/canada.py:148
+msgid "St. George's Day"
+msgstr "วันเซนต์จอร์จ (นิวฟันด์แลนด์และแลบราดอร์)"
+
+#: holidays/countries/canada.py:154
+msgid "Victoria Day"
+msgstr "วันวิคตอเรีย"
+
+#: holidays/countries/canada.py:156
+msgid "National Patriots' Day"
+msgstr "วันรำลึกกลุ่มแปตรีออต (ควิเบก)"
+
+#: holidays/countries/canada.py:160
+msgid "National Aboriginal Day"
+msgstr "วันชนพื้นเมือง (นอร์ทเวสต์เทร์ริทอรีส์)"
+
+#: holidays/countries/canada.py:164
+msgid "St. Jean Baptiste Day"
+msgstr "วันแซงต์-ฌ็อง-บาติสต์ (ควิเบก)"
+
+#: holidays/countries/canada.py:174 holidays/countries/canada.py:176
+msgid "Discovery Day"
+msgstr "วันแห่งการค้นภพ"
+
+#: holidays/countries/canada.py:183
+msgid "Memorial Day"
+msgstr "วันรำลึก (นิวฟันด์แลนด์และแลบราดอร์)"
+
+#: holidays/countries/canada.py:185
+msgid "Canada Day"
+msgstr "วันชาติแคนาดา"
+
+#: holidays/countries/canada.py:188
+msgid "Dominion Day"
+msgstr "วันราชอาณาจักรเครือจักรภพ"
+
+#: holidays/countries/canada.py:196
+msgid "Nunavut Day"
+msgstr "วันนูนาวุต"
+
+#: holidays/countries/canada.py:207
+msgid "Civic Holiday"
+msgstr "วันหยุดราชการ"
+
+#. British Columbia Day.
+#: holidays/countries/canada.py:217
+msgid "British Columbia Day"
+msgstr "วันบริติชโคลัมเบีย"
+
+#: holidays/countries/canada.py:222
+msgid "New Brunswick Day"
+msgstr "วันนิวบรันสวิก"
+
+#: holidays/countries/canada.py:227
+msgid "Saskatchewan Day"
+msgstr "วันซัสแคตเชวัน"
+
+#: holidays/countries/canada.py:233
+msgid "Labour Day"
+msgstr "วันแรงงาน"
+
+#: holidays/countries/canada.py:246
+msgid "Funeral of Her Majesty the Queen Elizabeth II"
+msgstr "พระราชพิธีพระบรมศพของสมเด็จพระราชินีนาถเอลิซาเบธที่ 2"
+
+#: holidays/countries/canada.py:254
+msgid "National Day for Truth and Reconciliation"
+msgstr "วันชาติแห่งความจริงและการปรองดอง"
+
+#: holidays/countries/canada.py:264 holidays/countries/canada.py:266
+msgid "Thanksgiving"
+msgstr "วันขอบคุณพระเจ้า"
+
+#: holidays/countries/canada.py:272
+msgid "Remembrance Day"
+msgstr "วันรำลึก"
+
+#. Christmas Day,
+#: holidays/countries/canada.py:283
+msgid "Christmas Day"
+msgstr "วันคริสต์มาส"
+
+#. Boxing Day.
+#: holidays/countries/canada.py:290
+msgid "Boxing Day"
+msgstr "วันเปิดกล่องของขวัญ"
diff --git a/holidays/locale/th/LC_MESSAGES/TH.po b/holidays/locale/th/LC_MESSAGES/TH.po
new file mode 100644
index 000000000..62e6514c8
--- /dev/null
+++ b/holidays/locale/th/LC_MESSAGES/TH.po
@@ -0,0 +1,172 @@
+# Thailand holidays Thai translation.
+# Authors: PPsyrius <ppsyrius@ppsyrius.dev>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-03-02 00:37+0700\n"
+"PO-Revision-Date: \n"
+"Last-Translator: PPsyrius <ppsyrius@ppsyrius.dev>\n"
+"Language-Team: Python Holidays Translation Team\n"
+"Language: th\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/thailand.py:119
+msgid "วันหยุดชดเชย"
+msgstr ""
+
+#: holidays/countries/thailand.py:120
+msgid "วันเลือกตั้ง"
+msgstr ""
+
+#: holidays/countries/thailand.py:121 holidays/countries/thailand.py:145
+#: holidays/countries/thailand.py:286 holidays/countries/thailand.py:309
+#: holidays/countries/thailand.py:366 holidays/countries/thailand.py:632
+#: holidays/countries/thailand.py:636
+#, c-format
+msgid "ชดเชย%s"
+msgstr ""
+
+#: holidays/countries/thailand.py:122
+msgid "วันหยุดพิเศษ (เพิ่มเติม)"
+msgstr ""
+
+#: holidays/countries/thailand.py:126
+msgid "พระราชพิธีกาญจนาภิเษก พ.ศ. 2539"
+msgstr ""
+
+#: holidays/countries/thailand.py:127
+msgid "พระราชพิธีฉลองสิริราชสมบัติครบ 60 ปี พ.ศ. 2549"
+msgstr ""
+
+#: holidays/countries/thailand.py:130
+msgid "วันหยุดพิเศษ (คมช.)"
+msgstr ""
+
+#: holidays/countries/thailand.py:131
+msgid "วันหยุดพิเศษ (การเมือง)"
+msgstr ""
+
+#: holidays/countries/thailand.py:132
+msgid "วันหยุดพิเศษ (มหาอุทกภัย พ.ศ. 2554)"
+msgstr ""
+
+#: holidays/countries/thailand.py:135
+msgid "วันหยุดพิเศษ (ร่วมถวายอาลัย ส่งดวงพระวิญญาณพระบรมศพ)"
+msgstr ""
+
+#: holidays/countries/thailand.py:138
+msgid "วันพระราชพิธีถวายพระเพลิงพระบรมศพพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช"
+msgstr ""
+
+#: holidays/countries/thailand.py:142
+msgid "พระราชพิธีบรมราชาภิเษก พระบาทสมเด็จพระวชิรเกล้าเจ้าอยู่หัว"
+msgstr ""
+
+#: holidays/countries/thailand.py:145 holidays/countries/thailand.py:339
+msgid "วันสงกรานต์"
+msgstr ""
+
+#: holidays/countries/thailand.py:298
+msgid "วันขึ้นปีใหม่"
+msgstr ""
+
+#: holidays/countries/thailand.py:309 holidays/countries/thailand.py:573
+msgid "วันสิ้นปี"
+msgstr ""
+
+#: holidays/countries/thailand.py:323
+msgid "วันจักรี"
+msgstr ""
+
+#: holidays/countries/thailand.py:388
+msgid "วันแรงงานแห่งชาติ"
+msgstr ""
+
+#: holidays/countries/thailand.py:400
+msgid "วันชาติ"
+msgstr ""
+
+#: holidays/countries/thailand.py:409
+msgid "วันฉัตรมงคล"
+msgstr ""
+
+#: holidays/countries/thailand.py:424
+msgid "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสุทิดา พัชรสุธาพิมลลักษณ พระบรมราชินี"
+msgstr ""
+
+#: holidays/countries/thailand.py:438
+msgid ""
+"วันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรเมนทรรามาธิบดีศรีสินทรมหาวชิราลงกรณ "
+"พระวชิรเกล้าเจ้าอยู่หัว"
+msgstr ""
+
+#: holidays/countries/thailand.py:456
+msgid "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสิริกิติ์ พระบรมราชินีนาถ"
+msgstr ""
+
+#: holidays/countries/thailand.py:464
+msgid "วันเฉลิมพระชนมพรรษาสมเด็จพระบรมราชชนนีพันปีหลวง"
+msgstr ""
+
+#: holidays/countries/thailand.py:475
+msgid "วันแม่แห่งชาติ"
+msgstr ""
+
+#: holidays/countries/thailand.py:491
+msgid "วันคล้ายวันสวรรคตพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+msgstr ""
+
+#: holidays/countries/thailand.py:499
+msgid ""
+"วันคล้ายวันสวรรคตพระบาทสมเด็จพระบรมชนกาธิเบศร มหาภูมิพลอดุลยเดชมหาราช บรมนาถบพิตร"
+msgstr ""
+
+#: holidays/countries/thailand.py:511
+msgid "วันปิยมหาราช"
+msgstr ""
+
+#: holidays/countries/thailand.py:524
+msgid "วันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+msgstr ""
+
+#: holidays/countries/thailand.py:532
+msgid "วันคล้ายวันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรมินทรมหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+msgstr ""
+
+#: holidays/countries/thailand.py:540
+msgid ""
+"วันคล้ายวันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระบรมชนกาธิเบศร มหาภูมิพลอดุลยเดชมหาราช "
+"บรมนาถบพิตร"
+msgstr ""
+
+#: holidays/countries/thailand.py:554
+msgid "วันพ่อแห่งชาติ"
+msgstr ""
+
+#: holidays/countries/thailand.py:563
+msgid "วันรัฐธรรมนูญ"
+msgstr ""
+
+#: holidays/countries/thailand.py:589
+msgid "วันมาฆบูชา"
+msgstr ""
+
+#: holidays/countries/thailand.py:597
+msgid "วันวิสาขบูชา"
+msgstr ""
+
+#: holidays/countries/thailand.py:606 holidays/countries/thailand.py:638
+msgid "วันอาสาฬหบูชา"
+msgstr ""
+
+#: holidays/countries/thailand.py:615 holidays/countries/thailand.py:634
+msgid "วันเข้าพรรษา"
+msgstr ""
+
+#: holidays/countries/thailand.py:652
+msgid "วันพืชมงคล"
+msgstr ""
diff --git a/holidays/locale/uk/LC_MESSAGES/AR.po b/holidays/locale/uk/LC_MESSAGES/AR.po
new file mode 100644
index 000000000..c7f899814
--- /dev/null
+++ b/holidays/locale/uk/LC_MESSAGES/AR.po
@@ -0,0 +1,126 @@
+# Argentina holidays Ukrainian translation.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-03-02 00:39+0700\n"
+"PO-Revision-Date: 2023-02-20 19:13+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: uk\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && "
+"n%10<=4 && (n%100<12 || n%100>14) ? 1 : 2);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/argentina.py:71
+msgid "Feriado con fines turísticos"
+msgstr "Додатковий вихідний"
+
+#: holidays/countries/argentina.py:75
+msgid "Bicentenario de la creación y primera jura de la bandera nacional"
+msgstr "200-річчя створення та першої присяги державному прапору"
+
+#: holidays/countries/argentina.py:78
+msgid "Bicentenario de la Batalla de Tucumán"
+msgstr "200-річчя битви при Тукумані"
+
+#: holidays/countries/argentina.py:79
+msgid ""
+"Bicentenario de la sesión inaugural de la Asamblea Nacional Constituyente "
+"del año 1813"
+msgstr ""
+"200-річчя інавгураційної сесії Національних установчих зборів 1813 року"
+
+#: holidays/countries/argentina.py:83
+msgid "Bicentenario de la Batalla de Salta"
+msgstr "200-річчя битви при Сальті"
+
+#: holidays/countries/argentina.py:84
+msgid "Censo nacional 2022"
+msgstr "День національного перепису 2022"
+
+#: holidays/countries/argentina.py:162 holidays/countries/argentina.py:165
+#, c-format
+msgid "%s (Observado)"
+msgstr "%s (вихідний)"
+
+#: holidays/countries/argentina.py:177
+msgid "Año Nuevo"
+msgstr "Новий рік"
+
+#: holidays/countries/argentina.py:185
+msgid "Día de Carnaval"
+msgstr "Карнавал"
+
+#: holidays/countries/argentina.py:194
+msgid "Día Nacional de la Memoria por la Verdad y la Justicia"
+msgstr "День пам'яті заради правди та правосуддя"
+
+#: holidays/countries/argentina.py:209
+msgid "Día del Veterano de Guerra"
+msgstr "День ветеранів війни"
+
+#: holidays/countries/argentina.py:211
+msgid "Día del Veterano y de los Caidos en la Guerra de Malvinas"
+msgstr "День ветеранів та загиблих на Мальвінській війні"
+
+#: holidays/countries/argentina.py:219
+msgid "Viernes Santo"
+msgstr "Страсна п'ятниця"
+
+#: holidays/countries/argentina.py:226
+msgid "Día del Trabajo"
+msgstr "День праці"
+
+#: holidays/countries/argentina.py:233
+msgid "Día de la Revolución de Mayo"
+msgstr "День Травневої революції"
+
+#: holidays/countries/argentina.py:244
+msgid ""
+"Día de los Derechos Argentinos sobre las Islas Malvinas, Sandwich y del "
+"Atlántico Sur"
+msgstr ""
+"День суверенітету Аргентини на Мальвінських, Сендвічевих і "
+"Південноатлантичних островах"
+
+#: holidays/countries/argentina.py:261
+msgid "Paso a la Inmortalidad del General Don Manuel Belgrano"
+msgstr "День пам’яті генерала Мануеля Бельграно"
+
+#: holidays/countries/argentina.py:270
+msgid "Día de la Independencia"
+msgstr "День незалежності"
+
+#: holidays/countries/argentina.py:275
+msgid "Inmaculada Concepción de María"
+msgstr "Непорочне зачаття Діви Марії"
+
+#: holidays/countries/argentina.py:280
+msgid "Navidad"
+msgstr "Різдво Христове"
+
+#: holidays/countries/argentina.py:290
+msgid "Paso a la Inmortalidad del General Don Martín Miguel de Güemes"
+msgstr "День пам'яті генерала Мартіна Мігеля де Гуемеса"
+
+#: holidays/countries/argentina.py:307
+msgid "Paso a la Inmortalidad del General Don José de San Martin"
+msgstr "День пам'яті генерала Хосе де Сан-Мартіна"
+
+#: holidays/countries/argentina.py:327
+msgid "Día del Respeto a la Diversidad Cultural"
+msgstr "День поваги до культурного різноманіття"
+
+#: holidays/countries/argentina.py:329
+msgid "Día de la Raza"
+msgstr "День Колумба"
+
+#: holidays/countries/argentina.py:340
+msgid "Día de la Soberanía Nacional"
+msgstr "День національного суверенітету"
diff --git a/holidays/locale/uk/LC_MESSAGES/CL.po b/holidays/locale/uk/LC_MESSAGES/CL.po
new file mode 100644
index 000000000..4a2c5feba
--- /dev/null
+++ b/holidays/locale/uk/LC_MESSAGES/CL.po
@@ -0,0 +1,133 @@
+# Chile holidays uk localization.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.21\n"
+"POT-Creation-Date: 2023-02-28 16:42+0200\n"
+"PO-Revision-Date: 2023-02-28 17:03+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: uk\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && n%10<=4 && (n%100<12 || n%100>14) ? 1 : 2);\n"
+"Generated-By: pygettext.py 1.5\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/chile.py:36 holidays/countries/chile.py:80
+msgid "Feriado nacional"
+msgstr "Національне свято"
+
+#. New Year's Day (Law 2.977)
+#: holidays/countries/chile.py:77
+msgid "Año Nuevo"
+msgstr "Новий рік"
+
+#: holidays/countries/chile.py:84
+msgid "Viernes Santo"
+msgstr "Страсна п'ятниця"
+
+#: holidays/countries/chile.py:85
+msgid "Sábado Santo"
+msgstr "Велика субота"
+
+#: holidays/countries/chile.py:89
+msgid "Ascensión del Señor"
+msgstr "Вознесіння Господнє"
+
+#: holidays/countries/chile.py:95
+msgid "Corpus Christi"
+msgstr "Свято Тіла і Крові Христових"
+
+#: holidays/countries/chile.py:99
+msgid "Día Nacional del Trabajo"
+msgstr "День праці"
+
+#. Naval Glories Day (Law 2.977)
+#: holidays/countries/chile.py:102
+msgid "Día de las Glorias Navales"
+msgstr "День військово-морської слави"
+
+#. National Day of Indigenous Peoples
+#: holidays/countries/chile.py:105
+msgid "Día Nacional de los Pueblos Indígenas"
+msgstr "Національний день корінних народів"
+
+#: holidays/countries/chile.py:121
+msgid "San Pedro y San Pablo"
+msgstr "День Святих Петра і Павла"
+
+#: holidays/countries/chile.py:127
+msgid "Virgen del Carmen"
+msgstr "Матір Божа Кармельська"
+
+#. Day of Assumption of the Virgin (Law 2.977)
+#: holidays/countries/chile.py:130
+msgid "Asunción de la Virgen"
+msgstr "Успіння Пресвятої Богородиці"
+
+#: holidays/countries/chile.py:134
+msgid "Día de la Liberación Nacional"
+msgstr "День національного визволення"
+
+#: holidays/countries/chile.py:139
+msgid "Día de la Unidad Nacional"
+msgstr "День національної єдності"
+
+#: holidays/countries/chile.py:146 holidays/countries/chile.py:150
+#: holidays/countries/chile.py:160 holidays/countries/chile.py:164
+msgid "Fiestas Patrias"
+msgstr "Національне свято"
+
+#. Independence Day (Law 2.977)
+#: holidays/countries/chile.py:153
+msgid "Día de la Independencia"
+msgstr "День Незалежності"
+
+#. Day of Glories of the Army of Chile (Law 2.977)
+#: holidays/countries/chile.py:156
+msgid "Día de las Glorias del Ejército"
+msgstr "День військової слави"
+
+#: holidays/countries/chile.py:169
+msgid "Día del Encuentro de dos Mundos"
+msgstr "День зустрічі двох світів"
+
+#: holidays/countries/chile.py:171
+msgid "Día de la Raza"
+msgstr "День Колумба"
+
+#: holidays/countries/chile.py:184
+msgid "Día Nacional de las Iglesias Evangélicas y Protestantes"
+msgstr "День Реформації"
+
+#. All Saints Day (Law 2.977)
+#: holidays/countries/chile.py:189
+msgid "Día de Todos los Santos"
+msgstr "День усіх святих"
+
+#. Immaculate Conception (Law 2.977)
+#: holidays/countries/chile.py:192
+msgid "La Inmaculada Concepción"
+msgstr "Свято Непорочного зачаття Пресвятої Діви Марії"
+
+#: holidays/countries/chile.py:195
+msgid "Víspera de Navidad"
+msgstr "Святий вечір"
+
+#. Christmas (Law 2.977)
+#: holidays/countries/chile.py:198
+msgid "Navidad"
+msgstr "Різдво Христове"
+
+#. Law 20.663
+#: holidays/countries/chile.py:203
+msgid "Asalto y Toma del Morro de Arica"
+msgstr "Штурм і захоплення Морро-де-Аріка"
+
+#. Law 20.678
+#: holidays/countries/chile.py:210
+msgid "Nacimiento del Prócer de la Independencia (Chillán y Chillán Viejo)"
+msgstr "Річниця Бернардо О'Гіґґінса (свято комун Чіллан і Чіллан В'єхо)"
diff --git a/holidays/locale/uk/LC_MESSAGES/CO.po b/holidays/locale/uk/LC_MESSAGES/CO.po
new file mode 100644
index 000000000..6b9675016
--- /dev/null
+++ b/holidays/locale/uk/LC_MESSAGES/CO.po
@@ -0,0 +1,102 @@
+# Colombia holidays uk localization.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-19 17:09+0200\n"
+"PO-Revision-Date: 2023-02-19 20:30+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: uk\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && n%10<=4 && (n%100<12 || n%100>14) ? 1 : 2);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/colombia.py:52
+#, c-format
+msgid "%s (Observado)"
+msgstr "%s (вихідний)"
+
+#. New Year's Day
+#: holidays/countries/colombia.py:60
+msgid "Año Nuevo"
+msgstr "Новий рік"
+
+#: holidays/countries/colombia.py:66
+msgid "Día de los Reyes Magos"
+msgstr "Богоявлення"
+
+#: holidays/countries/colombia.py:72
+msgid "Día de San José"
+msgstr "День Святого Йосипа"
+
+#. Labor Day
+#: holidays/countries/colombia.py:76
+msgid "Día del Trabajo"
+msgstr "День праці"
+
+#: holidays/countries/colombia.py:82
+msgid "San Pedro y San Pablo"
+msgstr "День Святих Петра і Павла"
+
+#. Independence Day
+#: holidays/countries/colombia.py:86
+msgid "Día de la Independencia"
+msgstr "День незалежності"
+
+#. Battle of Boyaca
+#: holidays/countries/colombia.py:89
+msgid "Batalla de Boyacá"
+msgstr "Річниця перемоги при Бояка"
+
+#: holidays/countries/colombia.py:95
+msgid "La Asunción"
+msgstr "Успіння Пресвятої Богородиці"
+
+#: holidays/countries/colombia.py:101
+msgid "Día de la Raza"
+msgstr "День Колумба"
+
+#: holidays/countries/colombia.py:108
+msgid "Día de Todos los Santos"
+msgstr "День усіх святих"
+
+#: holidays/countries/colombia.py:114
+msgid "Independencia de Cartagena"
+msgstr "День незалежності Картахени"
+
+#. Immaculate Conception
+#: holidays/countries/colombia.py:119
+msgid "La Inmaculada Concepción"
+msgstr "Свято Непорочного зачаття Пресвятої Діви Марії"
+
+#. Christmas
+#: holidays/countries/colombia.py:122
+msgid "Navidad"
+msgstr "Різдво Христове"
+
+#. Maundy Thursday
+#: holidays/countries/colombia.py:128
+msgid "Jueves Santo"
+msgstr "Великий четвер"
+
+#. Good Friday
+#: holidays/countries/colombia.py:131
+msgid "Viernes Santo"
+msgstr "Страсна п'ятниця"
+
+#: holidays/countries/colombia.py:136
+msgid "Ascensión del señor"
+msgstr "Вознесіння Господнє"
+
+#: holidays/countries/colombia.py:142
+msgid "Corpus Christi"
+msgstr "Свято Тіла і Крові Христових"
+
+#: holidays/countries/colombia.py:149
+msgid "Sagrado Corazón"
+msgstr "Свято Найсвятішого Серця Ісуса"
diff --git a/holidays/locale/uk/LC_MESSAGES/MC.po b/holidays/locale/uk/LC_MESSAGES/MC.po
new file mode 100644
index 000000000..3235d1b4f
--- /dev/null
+++ b/holidays/locale/uk/LC_MESSAGES/MC.po
@@ -0,0 +1,86 @@
+# Monaco holidays Ukrainian translation.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-20 11:58+0200\n"
+"PO-Revision-Date: 2023-02-20 12:23+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: uk\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && n%10<=4 && (n%100<12 || n%100>14) ? 1 : 2);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#: holidays/countries/monaco.py:31
+msgid "Jour férié"
+msgstr "Державне свято"
+
+#: holidays/countries/monaco.py:39
+#, c-format
+msgid "%s (Observé)"
+msgstr "%s (вихідний)"
+
+#. New Year's Day
+#: holidays/countries/monaco.py:45
+msgid "Le jour de l'An"
+msgstr "Новий рік"
+
+#. Saint Dévote's Day
+#: holidays/countries/monaco.py:48
+msgid "La Sainte Dévote"
+msgstr "День святої Девоти"
+
+#. Easter Monday
+#: holidays/countries/monaco.py:53
+msgid "Le lundi de Pâques"
+msgstr "Великодній понеділок"
+
+#. Labour Day
+#: holidays/countries/monaco.py:56
+msgid "Fête de la Travaille"
+msgstr "День праці"
+
+#. Ascension's Day
+#: holidays/countries/monaco.py:59
+msgid "L'Ascension"
+msgstr "Вознесіння Господнє"
+
+#. Whit Monday
+#: holidays/countries/monaco.py:62
+msgid "Le lundi de Pentecôte"
+msgstr "День Святого Духа"
+
+#. Corpus Christi
+#: holidays/countries/monaco.py:65
+msgid "La Fête Dieu"
+msgstr "Свято Тіла і Крові Христових"
+
+#. Assumption's Day
+#: holidays/countries/monaco.py:70
+msgid "L'Assomption de Marie"
+msgstr "Успіння Пресвятої Богородиці"
+
+#. All Saints' Day
+#: holidays/countries/monaco.py:74
+msgid "La Toussaint"
+msgstr "День усіх святих"
+
+#. Prince's Day
+#: holidays/countries/monaco.py:77
+msgid "La Fête du Prince"
+msgstr "День Князя"
+
+#. Immaculate Conception's Day
+#: holidays/countries/monaco.py:83
+msgid "L'Immaculée Conception"
+msgstr "Свято Непорочного зачаття Пресвятої Діви Марії"
+
+#. Christmas Day
+#: holidays/countries/monaco.py:86
+msgid "Noël"
+msgstr "Різдво Христове"
diff --git a/holidays/locale/uk/LC_MESSAGES/PE.po b/holidays/locale/uk/LC_MESSAGES/PE.po
new file mode 100644
index 000000000..5f3dc1a90
--- /dev/null
+++ b/holidays/locale/uk/LC_MESSAGES/PE.po
@@ -0,0 +1,93 @@
+# Peru holidays uk localization.
+# Authors: ~Jhellico <jhellico@gmail.com>, (c) 2023.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: Python Holidays 0.20\n"
+"POT-Creation-Date: 2023-02-21 15:18+0200\n"
+"PO-Revision-Date: 2023-02-21 15:19+0200\n"
+"Last-Translator: ~Jhellico <jhellico@gmail.com>\n"
+"Language-Team: Python Holidays localization team\n"
+"Language: uk\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && "
+"n%10<=4 && (n%100<12 || n%100>14) ? 1 : 2);\n"
+"Generated-By: Lingua 4.15.0\n"
+"X-Generator: Poedit 3.2.2\n"
+
+#. New Year's Day
+#: holidays/countries/peru.py:34
+msgid "Año Nuevo"
+msgstr "Новий рік"
+
+#. Holy Thursday
+#: holidays/countries/peru.py:38
+msgid "Jueves Santo"
+msgstr "Великий четвер"
+
+#. Good Friday
+#: holidays/countries/peru.py:41
+msgid "Viernes Santo"
+msgstr "Страсна п'ятниця"
+
+#. Easter Sunday
+#: holidays/countries/peru.py:44
+msgid "Domingo de Resurrección"
+msgstr "Великдень"
+
+#. Labor Day
+#: holidays/countries/peru.py:47
+msgid "Día del Trabajo"
+msgstr "День праці"
+
+#. Feast of Saints Peter and Paul
+#: holidays/countries/peru.py:50
+msgid "San Pedro y San Pablo"
+msgstr "День Святих Петра і Павла"
+
+#. Independence Day
+#: holidays/countries/peru.py:53
+msgid "Día de la Independencia"
+msgstr "День незалежності"
+
+#. Great Military Parade Day
+#: holidays/countries/peru.py:56
+msgid "Día de la Gran Parada Militar"
+msgstr "День Великого військового параду"
+
+#. Battle of Junín
+#: holidays/countries/peru.py:60
+msgid "Batalla de Junín"
+msgstr "День битви під Хуніном"
+
+#. Santa Rosa de Lima
+#: holidays/countries/peru.py:63
+msgid "Santa Rosa de Lima"
+msgstr "День Святої Рози Лімської"
+
+#. Battle of Angamos
+#: holidays/countries/peru.py:66
+msgid "Combate de Angamos"
+msgstr "День битви під Ангамосом"
+
+#. All Saints Day
+#: holidays/countries/peru.py:69
+msgid "Todos Los Santos"
+msgstr "День усіх святих"
+
+#. Immaculate Conception
+#: holidays/countries/peru.py:72
+msgid "Inmaculada Concepción"
+msgstr "Свято Непорочного зачаття Пресвятої Діви Марії"
+
+#. Battle of Ayacucho
+#: holidays/countries/peru.py:76
+msgid "Batalla de Ayacucho"
+msgstr "День битви при Аякучо"
+
+#. Christmas
+#: holidays/countries/peru.py:79
+msgid "Navidad del Señor"
+msgstr "Різдво Христове"
diff --git a/holidays/utils.py b/holidays/utils.py
index c3f99fd30..76637b70c 100755
--- a/holidays/utils.py
+++ b/holidays/utils.py
@@ -19,14 +19,8 @@
 
 import inspect
 import warnings
-from datetime import date
-from datetime import timedelta as td
-from functools import lru_cache
 from typing import Dict, Iterable, List, Optional, Union
 
-from hijri_converter import convert
-from hijri_converter.ummalqura import GREGORIAN_RANGE, HIJRI_RANGE
-
 from holidays import countries, financial
 from holidays.holiday_base import HolidayBase
 
@@ -307,886 +301,3 @@ def list_supported_financial(unique=False) -> Dict[str, List[str]]:
         for name, cls in inspect.getmembers(financial, inspect.isclass)
         if issubclass(cls, HolidayBase)
     }
-
-
-def _islamic_to_gre(g_year: int, h_month: int, h_day: int) -> Iterable[date]:
-    """
-    Find the Gregorian dates of all instances of Islamic (Lunar Hijrī) calendar
-    month and day falling within the Gregorian year. There could be up to two
-    such instances in a single Gregorian year since the Islamic (Lunar Hijrī)
-    calendar is about 11 days shorter.
-
-    Relies on package `hijri_converter
-    <https://www.pypi.org/project/hijri_converter>__.
-
-    :param g_year:
-        The Gregorian year.
-
-    :param h_month:
-        The Lunar Hijrī (Islamic) month.
-
-    :param h_day:
-        The Lunar Hijrī (Islamic) day.
-
-    :return:
-        An Iterable of Gregorian dates within the Gregorian year specified
-        that matches the Islamic (Lunar Hijrī) calendar day and month
-        specified. An empty Iterable is returned if the Gregorian year
-        is outside of the covered period, which as of hijri_converter 2.2.4
-        (in January 2023) is Gregorian years 1925 to 2076 inclusive, or
-        equal to the contents of hijri_converter.ummalqura.GREGORIAN_RANGE
-        plus/minus 1 year.
-    """
-
-    # To avoid hijri_converter check range OverflowError.
-    g_year_min, g_year_max = (d[0] for d in GREGORIAN_RANGE)
-    h_year_min, h_year_max = (d[0] for d in HIJRI_RANGE)
-    if g_year <= g_year_min or g_year > g_year_max:
-        return ()
-
-    h_year = convert.Gregorian(g_year, 1, 1).to_hijri().year
-    h_years = (
-        y for y in range(h_year, h_year + 3) if h_year_min <= y <= h_year_max
-    )
-    gre_dates = (
-        convert.Hijri(y, h_month, h_day).to_gregorian() for y in h_years
-    )
-    return (gre_date for gre_date in gre_dates if gre_date.year == g_year)
-
-
-class _ChineseLuniSolar:
-    def __init__(self) -> None:
-        """
-        This class has functions that generate Gregorian dates for holidays
-        based on the Chinese lunisolar calendar.
-
-        See `Wikipedia
-        <https://en.wikipedia.org/wiki/Chinese_New_Year#Dates_in_Chinese_\
-        lunisolar_calendar>`__
-
-        Usage example:
-
-        >>> from holidays.utils import _ChineseLuniSolar
-        >>> cnls = _ChineseLuniSolar()
-        >>> print(cnls.lunar_n_y_date(2010))
-        2010-02-14
-        """
-
-        # A binary representation starting from year 1901 of the number of
-        # days per year, and the number of days from the 1st to the 13th to
-        # store the monthly (including the month of the month). 1 means that
-        # the month is 30 days. 0 means the month is 29 days.
-        # The 12th to 15th digits indicate the month of the next month.
-        # If it is 0x0F, it means that there is no leap month.
-        self.G_LUNAR_MONTH_DAYS = [
-            0xF0EA4,  # 1901
-            0xF1D4A,
-            0x52C94,
-            0xF0C96,
-            0xF1536,
-            0x42AAC,
-            0xF0AD4,
-            0xF16B2,
-            0x22EA4,
-            0xF0EA4,  # 1911
-            0x6364A,
-            0xF164A,
-            0xF1496,
-            0x52956,
-            0xF055A,
-            0xF0AD6,
-            0x216D2,
-            0xF1B52,
-            0x73B24,
-            0xF1D24,  # 1921
-            0xF1A4A,
-            0x5349A,
-            0xF14AC,
-            0xF056C,
-            0x42B6A,
-            0xF0DA8,
-            0xF1D52,
-            0x23D24,
-            0xF1D24,
-            0x61A4C,  # 1931
-            0xF0A56,
-            0xF14AE,
-            0x5256C,
-            0xF16B4,
-            0xF0DA8,
-            0x31D92,
-            0xF0E92,
-            0x72D26,
-            0xF1526,
-            0xF0A56,  # 1941
-            0x614B6,
-            0xF155A,
-            0xF0AD4,
-            0x436AA,
-            0xF1748,
-            0xF1692,
-            0x23526,
-            0xF152A,
-            0x72A5A,
-            0xF0A6C,  # 1951
-            0xF155A,
-            0x52B54,
-            0xF0B64,
-            0xF1B4A,
-            0x33A94,
-            0xF1A94,
-            0x8152A,
-            0xF152E,
-            0xF0AAC,
-            0x6156A,  # 1961
-            0xF15AA,
-            0xF0DA4,
-            0x41D4A,
-            0xF1D4A,
-            0xF0C94,
-            0x3192E,
-            0xF1536,
-            0x72AB4,
-            0xF0AD4,
-            0xF16D2,  # 1971
-            0x52EA4,
-            0xF16A4,
-            0xF164A,
-            0x42C96,
-            0xF1496,
-            0x82956,
-            0xF055A,
-            0xF0ADA,
-            0x616D2,
-            0xF1B52,  # 1981
-            0xF1B24,
-            0x43A4A,
-            0xF1A4A,
-            0xA349A,
-            0xF14AC,
-            0xF056C,
-            0x60B6A,
-            0xF0DAA,
-            0xF1D92,
-            0x53D24,  # 1991
-            0xF1D24,
-            0xF1A4C,
-            0x314AC,
-            0xF14AE,
-            0x829AC,
-            0xF06B4,
-            0xF0DAA,
-            0x52D92,
-            0xF0E92,
-            0xF0D26,  # 2001
-            0x42A56,
-            0xF0A56,
-            0xF14B6,
-            0x22AB4,
-            0xF0AD4,
-            0x736AA,
-            0xF1748,
-            0xF1692,
-            0x53526,
-            0xF152A,  # 2011
-            0xF0A5A,
-            0x4155A,
-            0xF156A,
-            0x92B54,
-            0xF0BA4,
-            0xF1B4A,
-            0x63A94,
-            0xF1A94,
-            0xF192A,
-            0x42A5C,  # 2021
-            0xF0AAC,
-            0xF156A,
-            0x22B64,
-            0xF0DA4,
-            0x61D52,
-            0xF0E4A,
-            0xF0C96,
-            0x5192E,
-            0xF1956,
-            0xF0AB4,  # 2031
-            0x315AC,
-            0xF16D2,
-            0xB2EA4,
-            0xF16A4,
-            0xF164A,
-            0x63496,
-            0xF1496,
-            0xF0956,
-            0x50AB6,
-            0xF0B5A,  # 2041
-            0xF16D4,
-            0x236A4,
-            0xF1B24,
-            0x73A4A,
-            0xF1A4A,
-            0xF14AA,
-            0x5295A,
-            0xF096C,
-            0xF0B6A,
-            0x31B54,  # 2051
-            0xF1D92,
-            0x83D24,
-            0xF1D24,
-            0xF1A4C,
-            0x614AC,
-            0xF14AE,
-            0xF09AC,
-            0x40DAA,
-            0xF0EAA,
-            0xF0E92,  # 2061
-            0x31D26,
-            0xF0D26,
-            0x72A56,
-            0xF0A56,
-            0xF14B6,
-            0x52AB4,
-            0xF0AD4,
-            0xF16CA,
-            0x42E94,
-            0xF1694,  # 2071
-            0x8352A,
-            0xF152A,
-            0xF0A5A,
-            0x6155A,
-            0xF156A,
-            0xF0B54,
-            0x4174A,
-            0xF1B4A,
-            0xF1A94,
-            0x3392A,  # 2081
-            0xF192C,
-            0x7329C,
-            0xF0AAC,
-            0xF156A,
-            0x52B64,
-            0xF0DA4,
-            0xF1D4A,
-            0x41C94,
-            0xF0C96,
-            0x8192E,  # 2091
-            0xF0956,
-            0xF0AB6,
-            0x615AC,
-            0xF16D4,
-            0xF0EA4,
-            0x42E4A,
-            0xF164A,
-            0xF1516,
-            0x22936,  # 2100
-        ]
-        # Define range of years covered
-        self.START_YEAR = 1901
-        self.END_YEAR = 2099
-        # The 1st day of the 1st month of the Gregorian calendar is 1901/2/19
-        self.LUNAR_START_DATE = ((1901, 1, 1),)
-        self.SOLAR_START_DATE = date(1901, 2, 19)
-        # The Gregorian date for December 30, 2099 is 2100/2/8
-        self.LUNAR_END_DATE = (2099, 12, 30)
-        self.SOLAR_END_DATE = date(2100, 2, 18)
-
-    @lru_cache()
-    def _get_leap_month(self, lunar_year: int) -> int:
-        """
-        Calculate the leap lunar month in a lunar year.
-
-        :param lunar_year:
-            The lunar year.
-
-        :return:
-            The number of the leap month if one exists in the year, otherwise
-            15.
-        """
-        return (
-            self.G_LUNAR_MONTH_DAYS[lunar_year - self.START_YEAR] >> 16
-        ) & 0x0F
-
-    def _lunar_month_days(self, lunar_year: int, lunar_month: int) -> int:
-        """
-        Calculate the number of days in a lunar month.
-
-        :param lunar_year:
-            The lunar year.
-
-        :param lunar_month:
-            The lunar month of the lunar year.
-
-        :return:
-            The number of days in the lunar month.
-        """
-        return 29 + (
-            (
-                self.G_LUNAR_MONTH_DAYS[lunar_year - self.START_YEAR]
-                >> lunar_month
-            )
-            & 0x01
-        )
-
-    def _lunar_year_days(self, year: int) -> int:
-        """
-        Calculate the number of days in a lunar year.
-
-        :param year:
-            The lunar year.
-
-        :return:
-            The number of days in the lunar year.
-        """
-        days = 0
-        months_day = self.G_LUNAR_MONTH_DAYS[year - self.START_YEAR]
-        for i in range(1, 13 if self._get_leap_month(year) == 0x0F else 14):
-            day = 29 + ((months_day >> i) & 0x01)
-            days += day
-        return days
-
-    @lru_cache()
-    def _span_days(self, year: int) -> int:
-        """
-        Calculate the number of days elapsed since self.SOLAR_START_DATE to the
-        beginning of the year.
-
-        :param year:
-            The year.
-
-        :return:
-             The number of days since self.SOLAR_START_DATE.
-        """
-        span_days = 0
-        for y in range(self.START_YEAR, year):
-            span_days += self._lunar_year_days(y)
-        return span_days
-
-    def lunar_n_y_date(self, year: int) -> date:
-        """
-        Calculate the Gregorian date of Chinese Lunar New Year.
-
-        This is a faster implementation than calling
-        ``lunar_to_gre(year, 1, 1)``.
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            The Gregorian date of Chinese Lunar New Year.
-        """
-        # The Chinese calendar defines the lunar month containing the winter
-        # solstice as the eleventh month, which means that Chinese New Year
-        # usually falls on the second new moon after the winter solstice
-        # (rarely the third if an intercalary month intervenes). In more
-        # than 96 percent of the years, Chinese New Year's Day is the closest
-        # date to a new moon to lichun (Chinese: 立春; "start of spring") on 4
-        # or 5 February, and the first new moon after dahan (Chinese: 大寒;
-        # "major cold"). In the Gregorian calendar, the Chinese New Year begins
-        # at the new moon that falls between 21 January and 20 February.
-
-        span_days = self._span_days(year)
-        # Always in first month (by definition)
-        # leap_month = self._get_leap_month(year)
-        # for m in range(1, 1 + (1 > leap_month)):
-        #     span_days += self._lunar_month_days(year, m)
-        return self.SOLAR_START_DATE + td(days=span_days)
-
-    def lunar_to_gre(
-        self, year: int, month: int, day: int, leap: bool = True
-    ) -> date:
-        """
-        Calculate the Gregorian date of a Chinese lunar day and month in a
-        given Gregorian year.
-
-        :param year:
-            The Gregorian year.
-
-        :param year:
-            The Chinese lunar month.
-
-        :param year:
-            The Chinese lunar day.
-
-        :return:
-            The Gregorian date.
-        """
-        span_days = self._span_days(year)
-        leap_month = self._get_leap_month(year) if leap else 15
-        for m in range(1, month + (month > leap_month)):
-            span_days += self._lunar_month_days(year, m)
-        span_days += day - 1
-        return self.SOLAR_START_DATE + td(days=span_days)
-
-    def vesak_date(self, year: int) -> date:
-        """
-        Calculate the estimated Gregorian date of Vesak for Thailand, Laos,
-        Singapore and Indonesia, corresponding to the fourteenth day of the
-        fourth month in the Chinese lunar calendar. See `Wikipedia
-        <https://en.wikipedia.org/wiki/Vesak#Dates_of_observance>`__.
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Vesak (14th day of 4th month of the
-            lunar calendar).
-        """
-        span_days = self._span_days(year)
-        leap_month = self._get_leap_month(year)
-        for m in range(1, 4 + (4 > leap_month)):
-            span_days += self._lunar_month_days(year, m)
-        span_days += 14
-        return self.SOLAR_START_DATE + td(days=span_days)
-
-    def vesak_may_date(self, year: int) -> date:
-        """
-        Calculate the estimated Gregorian date of Vesak for Sri Lanka, Nepal,
-        India, Bangladesh and Malaysia, corresponding to the day of the
-        first full moon in May in the Gregorian calendar. See `Wikipedia
-        <https://en.wikipedia.org/wiki/Vesak#Dates_of_observance>`__.
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Vesak (first full moon in May).
-        """
-        span_days = self._span_days(year)
-        vesak_may_date = self.SOLAR_START_DATE + td(days=span_days + 14)
-        m = 1
-        while vesak_may_date.month < 5:
-            vesak_may_date += td(days=self._lunar_month_days(year, m))
-            m += 1
-        return vesak_may_date
-
-    def s_diwali_date(self, year: int) -> date:
-        """
-        Calculate the estimated Gregorian date of Southern India (Tamil)
-        Diwali.
-
-        Defined as the date of Amāvásyā (new moon) of Kārttikai, which
-        corresponds with the months of November or December in the Gregorian
-        calendar. See `Wikipedia <https://en.wikipedia.org/wiki/Diwali>`__.
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Southern India (Tamil) Diwali.
-        """
-        span_days = self._span_days(year)
-        leap_month = self._get_leap_month(year)
-        for m in range(1, 10 + (10 > leap_month)):
-            span_days += self._lunar_month_days(year, m)
-        span_days -= 2
-        return self.SOLAR_START_DATE + td(days=span_days)
-
-    def thaipusam_date(self, year: int) -> date:
-        """
-        Calculate the estimated Gregorian date of Thaipusam (Tamil).
-
-        Defined as the date of the full moon in the Tamil month of Thai, which
-        corresponds with the months of January or February in the Gregorian
-        calendar. See `Wikipedia <https://en.wikipedia.org/wiki/Thaipusam>`__.
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Thaipusam (Tamil).
-        """
-        span_days = self._span_days(year)
-        leap_month = self._get_leap_month(year)
-        for m in range(1, 1 + (leap_month <= 6)):
-            span_days += self._lunar_month_days(year, m)
-        span_days -= 15
-        return self.SOLAR_START_DATE + td(days=span_days)
-
-
-class _ThaiLuniSolar:
-    """
-    ** Thai Lunar Calendar Holidays only work from 1941 (B.E. 2484) onwards
-       until 2057 (B.E. 2600) as we only have Thai year-type data for
-       cross-checking until then.
-
-    So here are the basics of the Thai Lunar Calendar
-        3-year types for calendar intercalation:
-            - Pakatimat (Normal Year):
-                    consist of 12 months, has 354 days.
-            - Athikawan (Extra-Day Year): a
-                    add a day to the 7th month of the year, has 355 days
-                    for the synodic month correction.
-            - Athikamat (Extra-Month Year):
-                    we have the 8th month twice, has 384 days for the
-                    sidereal year correction.
-
-        Each month either has 30 (Even months) or 29 (Odd months)
-            - The waxing phase has 15 days until Full Moon and waning
-                phase 14 (Odd Months)/15 (Even Months/
-                Month 7 of Athikawan years) days for the New Moon.
-            - The second "Month 8" for Athikamat years is called
-                "Month 8.8", with all observed holy days delayed from
-                the usual calendar by 1 month.
-
-    List of public holidays dependent on the Thai Lunar Calendar:
-        - Magha Puja/Makha Bucha:
-                15th Waxing Day (Full Moon) of Month 3
-                (On Month 4 for Athikamat Years).
-        - Royal Ploughing Ceremony:
-                Based on this, though Court Astrologer picks the
-                auspicious dates, which sadly don't fall into a
-                predictable pattern; see its specific section below.
-        - Vesak/Visakha Bucha:
-                15th Waxing Day (Full Moon) of Month 6
-                (On Month 7 for Athikamat Years).
-        - Asalha Puja/Asarnha Bucha:
-                15th Waxing Day (Full Moon) of Month 8
-                (On Month 8/8 for Athikamat Years).
-        - Buddhist Lent Day/Wan Khao Phansa:
-                1st Waning Day of Month 8
-                (On Month 8/8 for Athikamat Years).
-
-    Other Buddhist date on Thai Lunar Calendar:
-        - Buddha's Cremation Day/Atthami Bucha
-                8th Waning Day of  Month 6
-                (On Month 7 for Athikamat Years).
-        - End of Buddhist Lent Day/Ok Phansa:
-                15th Waxing Day (Full Moon) of Month 11
-
-    The following code is based on Ninenik Narkdee's PHP implementation,
-    and we're thankful for his work.
-
-    Please avoid touching the Athikawan and Athikamat declaration array
-    at all costs unless you can find sources for them somewhere for 2057++
-
-    Sources: (Ninenik.com 's wbm) http://tiny.cc/wa_ninenik_thluncal_php
-             https://www.myhora.com/ปฏิทิน/ปฏิทิน-พ.ศ.2560.aspx
-
-    Usage example:
-
-    >>> from holidays.utils import _ThaiLuniSolar
-    >>> thls = _ThaiLuniSolar()
-    >>> print(thls.visakha_bucha_date(2010))
-    2010-05-28
-    """
-
-    # Athikawan (Extra-Day Year) list goes from 1941-2057 C.E.
-    # Copied off from 1757-2057 (B.E. 2300-2600) Thai Lunar Calendar
-    ATHIKAWAN_YEARS_GREGORIAN = {
-        1945,
-        1949,
-        1952,
-        1957,
-        1963,
-        1970,
-        1973,
-        1979,
-        1987,
-        1990,
-        1997,
-        2000,
-        2006,
-        2009,
-        2016,
-        2020,
-        2025,
-        2032,
-        2035,
-        2043,
-        2046,
-        2052,
-    }
-
-    # Athikamat (Extra-Month Year) list goes from 1941-2057 C.E.:
-    # Copied off from 1757-2057 (B.E. 2300-2600) Thai Lunar Calendar
-    # Approx formula as follows: (common_era-78)-0.45222)%2.7118886 < 1
-    ATHIKAMAT_YEARS_GREGORIAN = {
-        1942,
-        1944,
-        1947,
-        1950,
-        1953,
-        1956,
-        1958,
-        1961,
-        1964,
-        1966,
-        1969,
-        1972,
-        1975,
-        1977,
-        1980,
-        1983,
-        1985,
-        1988,
-        1991,
-        1994,
-        1996,
-        1999,
-        2002,
-        2004,
-        2007,
-        2010,
-        2012,
-        2015,
-        2018,
-        2021,
-        2023,
-        2026,
-        2029,
-        2031,
-        2034,
-        2037,
-        2040,
-        2042,
-        2045,
-        2048,
-        2050,
-        2053,
-        2056,
-    }
-
-    # While Buddhist Holy Days have been observed since the 1900s
-    #   Due to the calendar changes in 1941 (B.E. 2484) and that
-    #   our array only goes up to B.E. 2600; We'll thus only populate
-    #   the data for 1941-2057 (B.E. 2484-2600).
-    # Sources: หนังสือเวียนกรมการปกครอง กระทรวงมหาดไทย มท 0310.1/ว4 5 ก.พ. 2539
-    START_DATE = date(1940, 11, 30)
-    START_YEAR = 1941
-    END_YEAR = 2057
-
-    @lru_cache()
-    def _get_start_date(self, year: int) -> Optional[date]:
-        """
-        Calculate the start date of that particular Thai Lunar Calendar Year.
-        This usually falls in November or December of the previous Gregorian
-        year in question. Should the year be outside of working scope
-        (1941-2057: B.E 2484-2600), this will returns None instead.
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-             The start date of Thai Lunar Calendar for a Gregorian year.
-        """
-        if year < _ThaiLuniSolar.START_YEAR or year > _ThaiLuniSolar.END_YEAR:
-            return None
-
-        iter_start_date = _ThaiLuniSolar.START_DATE
-        iter_start_year = _ThaiLuniSolar.START_YEAR
-
-        while iter_start_year < year:
-            if iter_start_year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN:
-                delta_days = 384
-            elif iter_start_year in _ThaiLuniSolar.ATHIKAWAN_YEARS_GREGORIAN:
-                delta_days = 355
-            else:
-                delta_days = 354
-            iter_start_date += td(days=delta_days)
-            iter_start_year += 1
-        return iter_start_date
-
-    def makha_bucha_date(self, year: int) -> Optional[date]:
-        """
-        Calculate the estimated Gregorian date of Makha Bucha.
-        If the Gregorian year input is invalud, this will outputs None instead.
-
-        Also known as "Magha Puja". This concides with
-        the 15th Waxing Day of Month 3 in Thai Lunar Calendar,
-        or Month 4 in Athikamat years.
-
-        To calculate, we use use the following time delta:
-        - Athikamat: 15th Waxing Day of Month 4
-                     or 29[1] + 30[2] + 29[3] + 15[4] -1 = 102
-        - Athikawan: 15th Waxing Day of Month 3
-                     or 29[1] + 30[2] + 15[3] -1 = 73
-        - Pakatimat: 15th Waxing Day of Month 3
-                     or 29[1] + 30[2] + 15[3] -1 = 73
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Makha Bucha.
-        """
-        start_date = self._get_start_date(year)
-        if not start_date:
-            return None
-
-        return start_date + td(
-            days=+102
-            if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN
-            else +73
-        )
-
-    def visakha_bucha_date(self, year: int) -> Optional[date]:
-        """
-        Calculate the estimated Gregorian date of Visakha Bucha.
-        If the Gregorian year input is invalud, this will outputs None instead.
-
-        Also known as "Vesak" and "Buddha Day". This concides with
-        the 15th Waxing Day of Month 6 in Thai Lunar Calendar,
-        or Month 7 in Athikamat years.
-
-        To calculate, we use use the following time delta:
-        - Athikamat: 15th Waxing Day of Month 6
-                     or 177[1-6] + 15[7] -1 = 191
-        - Athikawan: 15th Waxing Day of Month 6
-                     or 147[1-5] + 15[6] -1 = 161
-        - Pakatimat: 15th Waxing Day of Month 6
-                     or 147[1-5] + 15[6] -1 = 161
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Visakha Bucha.
-        """
-        start_date = self._get_start_date(year)
-        if not start_date:
-            return None
-
-        return start_date + td(
-            days=+191
-            if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN
-            else +161
-        )
-
-    def atthami_bucha_date(self, year: int) -> Optional[date]:
-        """
-        Calculate the estimated Gregorian date of Atthami Bucha.
-        If the Gregorian year input is invalud, this will outputs None instead.
-
-        Also known as "Buddha's Cremation Day". This concides with
-        the 8th Waning Day of Month 6 in Thai Lunar Calendar,
-        or Month 7 in Athikamat years.
-
-        To calculate, we use use the following time delta:
-        - Athikamat: 8th Waning Day of  Month 7
-                    or 177[1-6] + 23[7] -1 = 199
-        - Athikawan: 8th Waning Day of  Month 6
-                     or 147[1-5] + 23[6] -1 = 169
-        - Pakatimat: 8th Waning Day of  Month 6
-                    or 147[1-5] + 23[6] -1 = 169
-        - Or as in simpler terms: "Visakha Bucha" +8
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Atthami Bucha.
-        """
-        start_date = self._get_start_date(year)
-        if not start_date:
-            return None
-
-        return start_date + td(
-            days=+199
-            if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN
-            else +169
-        )
-
-    def asarnha_bucha_date(self, year: int) -> Optional[date]:
-        """
-        Calculate the estimated Gregorian date of Asarnha Bucha.
-        If the Gregorian year input is invalud, this will outputs None instead.
-
-        Also known as "Asalha Puja". This concides with
-        the 15th Waxing Day of Month 8 in Thai Lunar Calendar,
-        or Month 8.8 in Athikamat years.
-
-        To calculate, we use use the following time delta:
-        - Athikamat: 15th Waxing Day of Month 8/8
-                     or 177[1-6] + 29[7] + 30[8] + 15[8.8] -1 = 250
-        - Athikawan: 15th Waxing Day of Month 8
-                     or 177[1-6] + 30[7] + 15[8] -1 = 221
-        - Pakatimat: 15th Waxing Day of Month 8
-                     or 177[1-6] + 29[7] + 15[8] -1 = 220
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Asarnha Bucha.
-        """
-        start_date = self._get_start_date(year)
-        if not start_date:
-            return None
-
-        if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN:
-            delta_days = 250
-        elif year in _ThaiLuniSolar.ATHIKAWAN_YEARS_GREGORIAN:
-            delta_days = 221
-        else:
-            delta_days = 220
-        return start_date + td(days=delta_days)
-
-    def khao_phansa_date(self, year: int) -> Optional[date]:
-        """
-        Calculate the estimated Gregorian date of Khao Phansa.
-        If the Gregorian year input is invalud, this will outputs None instead.
-
-        Also known as "(Start of) Buddhist Lent" and "Start of Vassa".
-        This concides with the 1st Waning Day of Month 8
-        in Thai Lunar Calendar, or Month 8.8 in Athikamat years.
-
-        To calculate, we use use the following time delta:
-        - Athikamat: 1st Waning Day of Month 8.8
-                     or 177[1-6] + 29[7] + 30[8] + 16[8.8] -1 = 251
-        - Athikawan: 1st Waning Day of Month 8 ]
-                     or 177[1-6] + 30[7] + 16[8] -1 = 222
-        - Pakatimat: 1st Waning Day of Month 8
-                     or 177[1-6] + 29[7] + 16[8] -1 = 221
-        - Or as in simpler terms: "Asarnha Bucha" +1
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Khao Phansa.
-        """
-        start_date = self._get_start_date(year)
-        if not start_date:
-            return None
-
-        if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN:
-            delta_days = 251
-        elif year in _ThaiLuniSolar.ATHIKAWAN_YEARS_GREGORIAN:
-            delta_days = 222
-        else:
-            delta_days = 221
-        return start_date + td(days=delta_days)
-
-    def ok_phansa_date(self, year: int) -> Optional[date]:
-        """
-        Calculate the estimated Gregorian date of Ok Phansa
-        If the Gregorian year input is invalud, this will outputs None instead.
-
-        Also known as "End of Buddhist Lent" and "End of Vassa".
-        This concides with the 15th Waxing Day of Month 11
-        in Thai Lunar Calendar.
-
-        To calculate, we use use the following time delta:
-        - Athikamat: 15th Waxing Day of Month 11
-                     or 295[1-10] + 30[8.8] + 15[11] -1 = 339
-        - Athikawan: 15th Waxing Day of Month 11
-                     or 295[1-10] + 1[7] + 15[11] -1 = 310
-        - Pakatimat: 15th Waxing Day of Month 11
-                     or 295[1-10] + 15[11] -1 = 309
-
-        :param year:
-            The Gregorian year.
-
-        :return:
-            Estimated Gregorian date of Ok Phansa.
-        """
-        start_date = self._get_start_date(year)
-        if not start_date:
-            return None
-
-        if year in _ThaiLuniSolar.ATHIKAMAT_YEARS_GREGORIAN:
-            delta_days = 339
-        elif year in _ThaiLuniSolar.ATHIKAWAN_YEARS_GREGORIAN:
-            delta_days = 310
-        else:
-            delta_days = 309
-        return start_date + td(days=delta_days)
diff --git a/setup.cfg b/setup.cfg
index 8432a6f34..285ac431c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -38,11 +38,13 @@ install_requires =
     hijri-converter
     korean-lunar-calendar
     python-dateutil
+    backports.zoneinfo;python_version<'3.9'
+    tzdata;os_name=='nt'
 python_requires = >=3.7
 include_package_data = True
 
 [bumpversion]
-current_version = 0.20
+current_version = 0.21
 
 [flake8]
 per-file-ignores =
diff --git a/tests/common.py b/tests/common.py
index eb6608d6c..1a4822415 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -20,7 +20,7 @@
 
 
 class TestCase(unittest.TestCase):
-    """Base class for python-holiday test cases."""
+    """Base class for python-holidays test cases."""
 
     @classmethod
     def setUpClass(cls, test_class=None):
@@ -32,10 +32,9 @@ def setUpClass(cls, test_class=None):
         cls.test_class = test_class
 
         if (
-            not hasattr(test_class, "default_language")
-            or test_class.default_language is None
+            hasattr(test_class, "default_language")
             # Can be either 2 (e.g., en, fr, uk) or 5 (e.g., en_US, en_GB).
-            or len(test_class.default_language) not in {2, 5}
+            and len(test_class.default_language) not in {2, 5}
         ):
             raise ValueError(
                 f"`{test_class.__name__}.default_language` value is invalid."
@@ -44,31 +43,37 @@ def setUpClass(cls, test_class=None):
     def setUp(self):
         super().setUp()
 
-        self.set_language(self.test_class.default_language)
+        if hasattr(self.test_class, "default_language"):
+            self.set_language(self.test_class.default_language)
+
         self.holidays = self.test_class()
+        self.holidays_non_observed = self.test_class(observed=False)
 
     def set_language(self, language):
         os.environ["LANGUAGE"] = language
 
-    def _parse_arguments(self, args, expand_items=True):
+    def _parse_arguments(
+        self, args, expand_items=True, instance_name="holidays"
+    ):
         item_args = args
         instance = None
 
-        if issubclass(args[0].__class__, HolidayBase):
+        if args and issubclass(args[0].__class__, HolidayBase):
             instance = args[0]
             item_args = args[1:]
         else:
             try:
-                instance = getattr(self, "holidays")
+                instance = getattr(self, instance_name)
                 self.assertTrue(
                     issubclass(instance.__class__, HolidayBase),
-                    "The `self.holidays` must be a `HolidayBase` subclass.",
+                    f"The `self.{instance_name}` must be a "
+                    "`HolidayBase` subclass.",
                 )
             except AttributeError:
                 raise ValueError(
                     "Either pass a holidays object (`HolidayBase` subclass) "
-                    "as a first argument or initialize `self.holidays` in the "
-                    "`setUp()` method."
+                    "as a first argument or initialize your `TestCase` class "
+                    "properly with `setUpClass()` method."
                 )
 
         items = []
@@ -83,6 +88,11 @@ def _parse_arguments(self, args, expand_items=True):
         else:
             items.extend(item_args)
 
+        if instance_name == "holidays":
+            self.assertTrue(instance.observed)
+        else:
+            self.assertFalse(instance.observed)
+
         return instance, items
 
     def _verify_type(self, holidays):
@@ -93,7 +103,6 @@ def _verify_type(self, holidays):
 
     def assertCountryAliases(self, cls, alpha_2, alpha_3):
         """Assert country aliases match."""
-
         self.assertTrue(
             issubclass(cls, HolidayBase),
             "Country holidays object must be a subclass of `HolidayBase`",
@@ -124,20 +133,37 @@ def assertCountryAliases(self, cls, alpha_2, alpha_3):
                 "look like alpha-3 country code."
             )
 
-    def assertHoliday(self, *args):
-        """Assert each date is a holiday."""
+    # Holiday.
+    def _assertHoliday(self, instance_name, *args):
+        """Helper: assert each date is a holiday."""
+        holidays, dates = self._parse_arguments(
+            args,
+            instance_name=instance_name,
+        )
+        self._verify_type(holidays)
 
-        holidays, dates = self._parse_arguments(args)
         for dt in dates:
             self.assertIn(dt, holidays, dt)
 
-    def assertHolidayDates(self, *args):
-        """Assert holiday dates exactly match expected dates."""
-
-        holidays, dates = self._parse_arguments(args)
+    def assertHoliday(self, *args):
+        """Assert each date is a holiday."""
+        self._assertHoliday("holidays", *args)
+
+    def assertNonObservedHoliday(self, *args):
+        """Assert each date is a non-observed holiday."""
+        self._assertHoliday("holidays_non_observed", *args)
+
+    # Holiday dates.
+    def _assertHolidayDates(self, instance_name, *args):
+        """Helper: assert holiday dates exactly match expected dates."""
+        holidays, dates = self._parse_arguments(
+            args,
+            instance_name=instance_name,
+        )
         self._verify_type(holidays)
 
-        for dt in dates:  # Check one by one for descriptive error messages.
+        # Check one by one for descriptive error messages.
+        for dt in dates:
             self.assertIn(dt, holidays, dt)
 
         self.assertEqual(
@@ -146,19 +172,42 @@ def assertHolidayDates(self, *args):
             set(dates).difference(holidays.keys()),
         )
 
-    def assertHolidayName(self, name, *args):
-        """Assert a holiday with a specific name exists."""
+    def assertHolidayDates(self, *args):
+        """Assert holiday dates exactly match expected dates."""
+        self._assertHolidayDates("holidays", *args)
 
-        holidays, _ = self._parse_arguments(args)
+    def assertNonObservedHolidayDates(self, *args):
+        """Assert holiday dates exactly match expected dates."""
+        self._assertHolidayDates("holidays_non_observed", *args)
+
+    # Holiday name.
+    def _assertHolidayName(self, name, instance_name, *args):
+        """Helper: assert a holiday with a specific name exists."""
+        holidays, _ = self._parse_arguments(
+            args,
+            instance_name=instance_name,
+        )
         self.assertEqual(
-            len(holidays.years), len(holidays.get_named(name)), name
+            len(holidays.years),
+            len(holidays.get_named(name, lookup="exact")),
+            name,
         )
 
-    def assertHolidays(self, *args):
-        """Assert holidays exactly match expected holidays."""
+    def assertHolidayName(self, name, *args):
+        """Assert a holiday with a specific name exists."""
+        self._assertHolidayName(name, "holidays", *args)
 
+    def assertNonObservedHolidayName(self, name, *args):
+        """Assert a non-observed holiday with a specific name exists."""
+        self._assertHolidayName(name, "holidays_non_observed", *args)
+
+    # Holidays.
+    def _assertHolidays(self, instance_name, *args):
+        """Helper: assert holidays exactly match expected holidays."""
         holidays, expected_holidays = self._parse_arguments(
-            args, expand_items=False
+            args,
+            expand_items=False,
+            instance_name=instance_name,
         )
         self._verify_type(holidays)
 
@@ -176,34 +225,87 @@ def assertHolidays(self, *args):
             ).difference((dt, name) for dt, name in expected_holidays),
         )
 
-    def assertHolidaysName(self, name, *args):
-        """Assert each holiday name matches an expected one."""
+    def assertHolidays(self, *args):
+        """Assert holidays exactly match expected holidays."""
+        self._assertHolidays("holidays", *args)
+
+    def assertNonObservedHolidays(self, *args):
+        """Assert non-observed holidays exactly match expected holidays."""
+        self._assertHolidays("holidays_non_observed", *args)
 
-        holidays, dates = self._parse_arguments(args)
+    # Holidays name.
+    def _assertHolidaysName(self, name, instance_name, *args):
+        """Assert each holiday name matches an expected one."""
+        holidays, dates = self._parse_arguments(
+            args,
+            instance_name=instance_name,
+        )
         for dt in dates:
             self.assertIn(name, holidays.get_list(dt))
 
-    def assertNoHoliday(self, *args):
-        """Assert each date is not a holiday."""
-
-        holidays, dates = self._parse_arguments(args)
+    def assertHolidaysName(self, name, *args):
+        """Assert each holiday name matches an expected one."""
+        self._assertHolidaysName(name, "holidays", *args)
+
+    def assertNonObservedHolidaysName(self, name, *args):
+        """Assert each non-observed holiday name matches an expected one."""
+        self._assertHolidaysName(name, "holidays_non_observed", *args)
+
+    # No holiday.
+    def _assertNoHoliday(self, instance_name, *args):
+        """Helper: assert each date is not a holiday."""
+        holidays, dates = self._parse_arguments(
+            args,
+            instance_name=instance_name,
+        )
         for dt in dates:
             self.assertNotIn(dt, holidays, dt)
 
+    def assertNoHoliday(self, *args):
+        """Assert each date is not a holiday."""
+        self._assertNoHoliday("holidays", *args)
+
+    def assertNoNonObservedHoliday(self, *args):
+        """Assert each date is not a non-observed holiday."""
+        self._assertNoHoliday("holidays_non_observed", *args)
+
+    # No holiday name.
+    def _assertNoHolidayName(self, name, instance_name, *args):
+        """Helper: assert a holiday with a specific name doesn't exist."""
+        holidays, _ = self._parse_arguments(
+            args,
+            instance_name=instance_name,
+        )
+        self.assertFalse(holidays.get_named(name, lookup="exact"), name)
+
     def assertNoHolidayName(self, name, *args):
         """Assert a holiday with a specific name doesn't exist."""
-
-        holidays, _ = self._parse_arguments(args)
-        self.assertFalse(holidays.get_named(name), name)
-
-    def assertNoHolidays(self, holidays):
-        """Assert holidays dict is empty."""
-
+        self._assertNoHolidayName(name, "holidays", *args)
+
+    def assertNoNonObservedHolidayName(self, name, *args):
+        """Assert a non-observed holiday with a specific name doesn't exist."""
+        self._assertNoHolidayName(name, "holidays_non_observed", *args)
+
+    # No holidays.
+    def _assertNoHolidays(self, instance_name, *args):
+        """Helper: assert holidays dict is empty."""
+        holidays, _ = self._parse_arguments(
+            args,
+            instance_name=instance_name,
+        )
         self._verify_type(holidays)
 
         self.assertFalse(holidays)
         self.assertEqual(0, len(holidays))
 
+    def assertNoHolidays(self, *args):
+        """Assert holidays dict is empty."""
+        self._assertNoHolidays("holidays", *args)
+
+    def assertNoNonObservedHolidays(self, *args):
+        """Assert non-observed holidays dict is empty."""
+        self._assertNoHolidays("holidays_non_observed", *args)
+
 
 class SundayHolidays(TestCase):
     """Common class to test countries with Sundays as a holidays."""
diff --git a/tests/countries/__init__.py b/tests/countries/__init__.py
index 74e93d096..e69de29bb 100644
--- a/tests/countries/__init__.py
+++ b/tests/countries/__init__.py
@@ -1,27 +0,0 @@
-#  python-holidays
-#  ---------------
-#  A fast, efficient Python library for generating country, province and state
-#  specific sets of holidays on the fly. It aims to make determining whether a
-#  specific date is a holiday as fast and flexible as possible.
-#
-#  Authors: dr-prodigy <dr.prodigy.github@gmail.com> (c) 2017-2023
-#           ryanss <ryanssdev@icloud.com> (c) 2014-2017
-#  Website: https://github.com/dr-prodigy/python-holidays
-#  License: MIT (see LICENSE file)
-import pkgutil
-from importlib.abc import MetaPathFinder, PathEntryFinder
-from typing import Union
-
-loader: Union[MetaPathFinder, PathEntryFinder]
-module_name: str
-is_pkg: bool
-
-__all__ = []
-for loader, module_name, is_pkg in pkgutil.walk_packages(__path__):
-    __all__.append(module_name)
-    _module = loader.find_module(  # type: ignore[union-attr]
-        module_name
-    ).load_module(  # type: ignore[call-arg]
-        module_name
-    )
-    globals()[module_name] = _module
diff --git a/tests/countries/test_albania.py b/tests/countries/test_albania.py
index fdac6e1dc..b88e758c9 100644
--- a/tests/countries/test_albania.py
+++ b/tests/countries/test_albania.py
@@ -14,8 +14,9 @@
 
 
 class TestAlbania(TestCase):
-    def setUp(self):
-        self.holidays = Albania()
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Albania)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Albania, AL, ALB)
@@ -177,7 +178,7 @@ def test_observed(self):
             "2084-05-02",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Albania(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_2022(self):
         self.assertHolidays(
diff --git a/tests/countries/test_angola.py b/tests/countries/test_angola.py
index ce0a41baf..868ffb196 100644
--- a/tests/countries/test_angola.py
+++ b/tests/countries/test_angola.py
@@ -14,15 +14,20 @@
 
 
 class TestAngola(TestCase):
-    def setUp(self):
-        self.holidays = Angola()
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Angola)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Angola, AO, AGO)
 
     def test_no_holidays(self):
+        self.assertNoHolidays()
         self.assertNoHolidays(Angola(years=1974))
 
+        self.assertNoNonObservedHolidays()
+        self.assertNoNonObservedHolidays(Angola(observed=False, years=1974))
+
     def test_carnival(self):
         self.assertHoliday(
             "1994-02-15",
@@ -159,4 +164,4 @@ def test_observed(self):
             "2025-12-26",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Angola(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
diff --git a/tests/countries/test_argentina.py b/tests/countries/test_argentina.py
index edefb02f2..016907b22 100644
--- a/tests/countries/test_argentina.py
+++ b/tests/countries/test_argentina.py
@@ -9,11 +9,7 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-from datetime import date
-from datetime import timedelta as td
-
-from holidays.constants import MAY, JUN, JUL, AUG, OCT
-from holidays.countries.argentina import AR, ARG, Argentina
+from holidays.countries.argentina import Argentina, AR, ARG
 from tests.common import TestCase
 
 
@@ -26,26 +22,16 @@ def test_country_aliases(self):
         self.assertCountryAliases(Argentina, AR, ARG)
 
     def test_new_years_day(self):
-        self.holidays.observed = False
-        self.assertNoHoliday(
-            "2010-12-31",
-            "2017-01-02",
-        )
+        self.assertHoliday(f"{year}-01-01" for year in range(1950, 2050))
 
-        self.holidays.observed = True
-        self.assertHoliday(
-            "2017-01-01",
-        )
+    def test_carnival_day(self):
+        name = "Día de Carnaval"
 
-        for year in range(1900, 2100):
-            dt = date(year, 1, 1)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
+        self.assertNoHolidayName(name, Argentina(years=1955))
+        self.assertHolidaysName(name, Argentina(years=range(1956, 1976)))
+        self.assertNoHolidayName(name, Argentina(years=range(1976, 2011)))
+        self.assertHolidaysName(name, Argentina(years=range(2011, 2050)))
 
-    def test_carnival_day(self):
         self.assertHoliday(
             "2016-02-08",
             "2016-02-09",
@@ -53,178 +39,189 @@ def test_carnival_day(self):
             "2017-02-28",
             "2018-02-12",
             "2018-02-13",
+            "2019-03-04",
+            "2019-03-05",
+            "2020-02-24",
+            "2020-02-25",
+            "2021-02-15",
+            "2021-02-16",
+            "2022-02-28",
+            "2022-03-01",
+            "2023-02-20",
+            "2023-02-21",
         )
 
     def test_memory_national_day(self):
-        self.holidays.observed = False
-        self.assertNoHoliday(
-            "1907-03-24",
-            "2002-03-24",
-        )
-
-        self.holidays.observed = True
-        self.assertHoliday(
-            "2018-03-24",
-            "2017-03-24",
-            "2016-03-24",
+        self.assertHoliday(f"{year}-03-24" for year in range(2006, 2050))
+        self.assertNoHolidayName(
+            "Día Nacional de la Memoria por la Verdad y la Justicia",
+            Argentina(years=range(1950, 2006)),
         )
 
-    def test_holy_week_day(self):
+    def test_good_friday(self):
         self.assertHoliday(
-            "2016-03-24",
             "2016-03-25",
-            "2017-04-13",
             "2017-04-14",
-            "2018-03-29",
             "2018-03-30",
+            "2019-04-19",
+            "2020-04-10",
+            "2021-04-02",
+            "2022-04-15",
+            "2023-04-07",
         )
 
     def test_malvinas_war_day(self):
-        self.assertHoliday(*[f"{year}-04-02" for year in range(1900, 2100)])
-
-    def test_labor_day(self):
-        self.holidays.observed = False
-        self.assertNoHoliday(
-            "2010-04-30",
-            "2011-05-02",
+        name_veterans = "Día del Veterano de Guerra"
+        name_malvinas = (
+            "Día del Veterano y de los Caidos en la Guerra de Malvinas"
         )
 
-        self.holidays.observed = True
-        self.assertHoliday(
-            "1922-05-01",
+        self.assertNoHolidayName(name_veterans, Argentina(years=1992))
+        self.assertNoHolidayName(
+            name_malvinas,
+            Argentina(years=range(1950, 2001)),
+        )
+        self.assertHolidaysName(
+            name_veterans, Argentina(years=range(1992, 2001))
+        )
+        self.assertHolidaysName(
+            name_malvinas, Argentina(years=range(2001, 2050))
         )
+        self.assertHoliday(f"{year}-04-02" for year in range(1993, 2020))
+        self.assertHoliday("2020-03-31")
+        self.assertHoliday(f"{year}-04-02" for year in range(2021, 2050))
 
-        for year in range(1900, 2100):
-            dt = date(year, MAY, 1)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
+    def test_labor_day(self):
+        self.assertNoHolidayName("Día del Trabajo", Argentina(years=1929))
+        self.assertHoliday(f"{year}-05-01" for year in range(1930, 2050))
 
     def test_may_revolution_day(self):
-        self.holidays.observed = False
-        self.assertNoHoliday(
-            "1930-05-25",
-            "2014-05-25",
+        self.assertNoHolidayName(
+            "Día de la Revolución de Mayo", Argentina(years=1812)
+        )
+        self.assertHoliday(f"{year}-05-25" for year in range(1813, 2050))
+
+    def test_sovereignty_over_malvinas_day(self):
+        name = (
+            "Día de los Derechos Argentinos sobre las Islas Malvinas, "
+            "Sandwich y del Atlántico Sur"
         )
 
-        self.holidays.observed = True
-        for year in range(1900, 2100):
-            dt = date(year, MAY, 25)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
+        self.assertNoHolidayName(name, Argentina(years=1982))
+        self.assertNoHolidayName(name, Argentina(years=range(2001, 2050)))
+        self.assertHoliday("1983-04-02")
+        self.assertHoliday(f"{year}-06-10" for year in range(1984, 2001))
+        self.assertNoHoliday(f"{year}-06-10" for year in range(2001, 2050))
 
     def test_guemes_day(self):
-        for year in range(1900, 2100):
-            dt = date(year, JUN, 17)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
+        self.assertNonObservedHoliday(
+            (f"{year}-06-17" for year in range(2016, 2050)),
+        )
+        self.assertNoHolidayName(
+            "Paso a la Inmortalidad del General Don Martín Miguel de Güemes",
+            Argentina(years=range(1950, 2016)),
+        )
+        self.assertHoliday(
+            "2016-06-17",
+            "2017-06-17",
+            "2018-06-17",
+            "2019-06-17",
+            "2020-06-15",
+            "2021-06-21",
+            "2022-06-17",
+            "2023-06-17",
+        )
 
     def test_belgrano_day(self):
-        for year in range(1900, 2100):
-            dt = date(year, JUN, 20)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
+        self.assertHoliday(f"{year}-06-20" for year in range(1938, 1995))
+        self.assertHoliday(f"{year}-06-20" for year in range(2011, 2050))
+        self.assertHoliday(
+            "2001-06-18",
+            "2002-06-17",
+            "2003-06-16",
+            "2004-06-21",
+            "2005-06-20",
+            "2006-06-19",
+            "2007-06-18",
+            "2008-06-16",
+            "2009-06-15",
+            "2010-06-21",
+        )
 
     def test_independence_day(self):
-        self.holidays.observed = False
-        self.assertNoHoliday(
-            "2011-07-09",
-            "2017-07-09",
+        self.assertNoHolidayName(
+            "Día de la Independencia", Argentina(years=1815)
         )
+        self.assertHoliday(f"{year}-07-09" for year in range(1816, 2050))
 
-        self.holidays.observed = True
+    def test_san_martin_day(self):
+        self.assertNoHolidayName(
+            "Paso a la Inmortalidad del General Don José de San Martin",
+            Argentina(years=1937),
+        )
+        self.assertNonObservedHoliday(
+            (f"{year}-08-17" for year in range(1938, 1995)),
+        )
         self.assertHoliday(
-            "2011-07-09",
-            "2017-07-09",
+            "2011-08-22",
+            "2015-08-17",
+            "2016-08-15",
+            "2017-08-21",
+            "2018-08-20",
+            "2019-08-17",
+            "2020-08-17",
+            "2021-08-16",
+            "2022-08-15",
+            "2023-08-21",
         )
 
-        for year in range(1900, 2100):
-            dt = date(year, JUL, 9)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
+    def test_cultural_day(self):
+        name_raza = "Día de la Raza"
+        name_cultural = "Día del Respeto a la Diversidad Cultural"
 
-    def test_san_martin_day(self):
-        self.holidays.observed = False
-        self.assertNoHoliday(
-            "1930-08-10",
-            "2008-08-10",
+        self.assertNoHolidayName(name_raza, Argentina(years=1916))
+        self.assertNoHolidayName(
+            name_cultural, Argentina(years=range(1917, 2010))
         )
+        self.assertNoHolidayName(name_raza, Argentina(years=range(2010, 2050)))
 
-        self.holidays.observed = True
-        for year in range(1900, 2100):
-            dt = date(year, AUG, 17)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
-
-    def test_cultural_day(self):
-        self.holidays.observed = False
-        self.assertNoHoliday(
-            "1913-10-12",
-            "2014-10-12",
+        self.assertNonObservedHoliday(
+            (f"{year}-10-12" for year in range(1917, 2050)),
+        )
+        self.assertHoliday(
+            "2015-10-12",
+            "2016-10-10",
+            "2017-10-16",
+            "2018-10-15",
+            "2019-10-12",
+            "2020-10-12",
+            "2021-10-11",
+            "2022-10-10",
+            "2023-10-16",
         )
-
-        self.holidays.observed = True
-        for year in range(1900, 2100):
-            dt = date(year, OCT, 12)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
 
     def test_national_sovereignty_day(self):
-        for year in range(1900, 2100):
-            dt = date(year, 11, 20)
-            if year < 2010:
-                self.assertNoHoliday(dt)
-            else:
-                self.assertHoliday(dt)
-                self.assertNoHoliday(
-                    dt + td(days=-1),
-                    dt + td(days=+1),
-                )
-
-    def test_immaculate_conception_day(self):
-        self.holidays.observed = False
-        self.assertNoHoliday(
-            "1940-12-08",
-            "2013-12-08",
+        self.assertNoHoliday(f"{year}-11-20" for year in range(1950, 2010))
+        self.assertNonObservedHoliday(
+            (f"{year}-11-20" for year in range(2010, 2015)),
+        )
+        self.assertHoliday(
+            "2015-11-27",
+            "2016-11-28",
+            "2017-11-20",
+            "2018-11-19",
+            "2019-11-18",
+            "2020-11-23",
+            "2021-11-22",
+            "2022-11-20",
+            "2023-11-20",
         )
 
-        self.holidays.observed = True
-        for year in range(1900, 2100):
-            dt = date(year, 12, 8)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
+    def test_immaculate_conception_day(self):
+        self.assertHoliday(f"{year}-12-08" for year in range(1950, 2050))
 
     def test_christmas(self):
-        for year in range(1900, 2100):
-            dt = date(year, 12, 25)
-            self.assertHoliday(dt)
-            self.assertNoHoliday(
-                dt + td(days=-1),
-                dt + td(days=+1),
-            )
+        self.assertHoliday(f"{year}-12-25" for year in range(1950, 2050))
 
     def test_2022(self):
         self.assertHolidays(
@@ -248,54 +245,63 @@ def test_2022(self):
                 "2022-04-02",
                 "Día del Veterano y de los Caidos en la Guerra de Malvinas",
             ),
-            (
-                "2022-04-14",
-                "Semana Santa (Jueves Santo)",
-            ),
             (
                 "2022-04-15",
-                "Semana Santa (Viernes Santo)",
-            ),
-            (
-                "2022-04-17",
-                "Día de Pascuas",
+                "Viernes Santo",
             ),
             (
                 "2022-05-01",
                 "Día del Trabajo",
             ),
+            (
+                "2022-05-18",
+                "Censo nacional 2022",
+            ),
             (
                 "2022-05-25",
                 "Día de la Revolución de Mayo",
             ),
             (
                 "2022-06-17",
-                "Día Pase a la Inmortalidad del General Martín Miguel de "
+                "Paso a la Inmortalidad del General Don Martín Miguel de "
                 "Güemes",
             ),
             (
                 "2022-06-20",
-                "Día Pase a la Inmortalidad del General D. Manuel Belgrano",
+                "Paso a la Inmortalidad del General Don Manuel Belgrano",
             ),
             (
                 "2022-07-09",
                 "Día de la Independencia",
             ),
             (
-                "2022-08-17",
-                "Día Pase a la Inmortalidad del General D. José de San Martin",
+                "2022-08-15",
+                "Paso a la Inmortalidad del General Don José de San Martin "
+                "(Observado)",
             ),
             (
-                "2022-10-12",
-                "Día del Respeto a la Diversidad Cultural",
+                "2022-10-07",
+                "Feriado con fines turísticos",
+            ),
+            (
+                "2022-10-10",
+                "Día del Respeto a la Diversidad Cultural (Observado)",
             ),
             (
                 "2022-11-20",
-                "Día Nacional de la Soberanía",
+                "Día de la Soberanía Nacional",
+            ),
+            (
+                "2022-11-21",
+                "Feriado con fines turísticos",
             ),
             (
                 "2022-12-08",
-                "La Inmaculada Concepción",
+                "Inmaculada Concepción de María",
+            ),
+            (
+                "2022-12-09",
+                "Feriado con fines turísticos",
             ),
             (
                 "2022-12-25",
@@ -303,6 +309,88 @@ def test_2022(self):
             ),
         )
 
+    def test_2023(self):
+        self.assertHolidays(
+            (
+                "2023-01-01",
+                "Año Nuevo",
+            ),
+            (
+                "2023-02-20",
+                "Día de Carnaval",
+            ),
+            (
+                "2023-02-21",
+                "Día de Carnaval",
+            ),
+            (
+                "2023-03-24",
+                "Día Nacional de la Memoria por la Verdad y la Justicia",
+            ),
+            (
+                "2023-04-02",
+                "Día del Veterano y de los Caidos en la Guerra de Malvinas",
+            ),
+            (
+                "2023-04-07",
+                "Viernes Santo",
+            ),
+            (
+                "2023-05-01",
+                "Día del Trabajo",
+            ),
+            (
+                "2023-05-25",
+                "Día de la Revolución de Mayo",
+            ),
+            (
+                "2023-05-26",
+                "Feriado con fines turísticos",
+            ),
+            (
+                "2023-06-17",
+                "Paso a la Inmortalidad del General Don Martín Miguel de "
+                "Güemes",
+            ),
+            (
+                "2023-06-19",
+                "Feriado con fines turísticos",
+            ),
+            (
+                "2023-06-20",
+                "Paso a la Inmortalidad del General Don Manuel Belgrano",
+            ),
+            (
+                "2023-07-09",
+                "Día de la Independencia",
+            ),
+            (
+                "2023-08-21",
+                "Paso a la Inmortalidad del General Don José de San Martin "
+                "(Observado)",
+            ),
+            (
+                "2023-10-13",
+                "Feriado con fines turísticos",
+            ),
+            (
+                "2023-10-16",
+                "Día del Respeto a la Diversidad Cultural (Observado)",
+            ),
+            (
+                "2023-11-20",
+                "Día de la Soberanía Nacional",
+            ),
+            (
+                "2023-12-08",
+                "Inmaculada Concepción de María",
+            ),
+            (
+                "2023-12-25",
+                "Navidad",
+            ),
+        )
+
     def test_l10n_default(self):
         def run_tests(languages):
             for language in languages:
@@ -319,11 +407,24 @@ def test_l10n_en_us(self):
         en_us = "en_US"
 
         ar = Argentina(language=en_us)
-        self.assertEqual(ar["2018-01-01"], "New Year's Day")
+        self.assertEqual(ar["2022-01-01"], "New Year's Day")
         self.assertEqual(ar["2022-12-25"], "Christmas")
 
         self.set_language(en_us)
         for language in (None, en_us, "invalid"):
             ar = Argentina(language=language)
-            self.assertEqual(ar["2018-01-01"], "New Year's Day")
+            self.assertEqual(ar["2022-01-01"], "New Year's Day")
             self.assertEqual(ar["2022-12-25"], "Christmas")
+
+    def test_l10n_uk(self):
+        uk = "uk"
+
+        ar = Argentina(language=uk)
+        self.assertEqual(ar["2022-01-01"], "Новий рік")
+        self.assertEqual(ar["2022-12-25"], "Різдво Христове")
+
+        self.set_language(uk)
+        for language in (None, uk, "invalid"):
+            ar = Argentina(language=language)
+            self.assertEqual(ar["2022-01-01"], "Новий рік")
+            self.assertEqual(ar["2022-12-25"], "Різдво Христове")
diff --git a/tests/countries/test_australia.py b/tests/countries/test_australia.py
index 39f557a99..2dac60554 100644
--- a/tests/countries/test_australia.py
+++ b/tests/countries/test_australia.py
@@ -336,11 +336,13 @@ def test_christmas_day(self):
             self.assertNotIn(dt + td(days=-1), self.holidays)
         self.assertNotIn(date(2010, 12, 24), self.holidays)
         self.assertNotEqual(
-            self.holidays[date(2011, 12, 26)], "Christmas Day (Observed)"
+            self.holidays[date(2011, 12, 26)],
+            "Christmas Day (Observed)",
         )
         self.holidays.observed = True
         self.assertEqual(
-            self.holidays[date(2011, 12, 27)], "Christmas Day (Observed)"
+            self.holidays[date(2011, 12, 27)],
+            "Christmas Day (Observed)",
         )
         for year, day in enumerate(
             [
diff --git a/tests/countries/test_azerbaijan.py b/tests/countries/test_azerbaijan.py
index 6ada64b19..977dec248 100644
--- a/tests/countries/test_azerbaijan.py
+++ b/tests/countries/test_azerbaijan.py
@@ -14,8 +14,9 @@
 
 
 class TestAzerbaijan(TestCase):
-    def setUp(self):
-        self.holidays = Azerbaijan()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Azerbaijan)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Azerbaijan, AZ, AZE)
@@ -31,6 +32,9 @@ def test_new_year(self):
     def test_black_january(self):
         self.assertHoliday(f"{year}-01-20" for year in range(2000, 2050))
         self.assertNoHoliday(f"{year}-01-20" for year in range(1990, 2000))
+        self.assertNoHolidayName(
+            "Black January", Azerbaijan(years=range(1990, 2000))
+        )
 
     def test_int_women_day(self):
         self.assertHoliday(f"{year}-03-08" for year in range(1990, 2050))
@@ -44,8 +48,7 @@ def test_novruz(self):
                 f"{year}-03-23",
                 f"{year}-03-24",
             )
-        for year in range(1990, 2007):
-            self.assertEqual(Azerbaijan(years=year).get_named("Novruz"), [])
+        self.assertNoHolidayName("Novruz", Azerbaijan(years=range(1990, 2007)))
 
     def test_victory_day_may(self):
         self.assertHoliday(f"{year}-05-09" for year in range(1990, 2050))
@@ -53,16 +56,12 @@ def test_victory_day_may(self):
     def test_republic_day(self):
         self.assertHoliday(f"{year}-05-28" for year in range(1992, 2050))
         self.assertNoHoliday(f"{year}-05-28" for year in range(1990, 1992))
-        for year in range(1992, 2021):
-            self.assertIn(
-                "Republic Day",
-                Azerbaijan(years=year).get_list(f"{year}-05-28"),
-            )
-        for year in range(2021, 2050):
-            self.assertIn(
-                "Independence Day",
-                Azerbaijan(years=year).get_list(f"{year}-05-28"),
-            )
+        self.assertHolidaysName(
+            "Republic Day", (f"{year}-05-28" for year in range(1992, 2021))
+        )
+        self.assertHolidaysName(
+            "Independence Day", (f"{year}-05-28" for year in range(2021, 2001))
+        )
 
     def test_salvation_day(self):
         self.assertHoliday(f"{year}-06-15" for year in range(1997, 2050))
@@ -99,16 +98,21 @@ def test_int_solidarity_day(self):
 
     def test_hijri_based(self):
         # Ramazan Bayrami
-        self.assertHoliday(
+        for dt in (
             "2020-05-24",
             "2020-05-25",
             "2021-05-13",
             "2021-05-14",
             "2022-05-02",
             "2022-05-03",
-        )
+        ):
+            self.assertIn("Ramazan Bayrami", self.holidays[dt])
+
         # Gurban Bayrami
-        self.assertHoliday(
+        for dt in (
+            "2006-01-10",
+            "2006-01-11",
+            "2006-12-31",
             "2020-07-31",
             "2020-08-01",
             "2020-08-03",
@@ -118,7 +122,8 @@ def test_hijri_based(self):
             "2022-07-10",
             "2022-07-11",
             "2022-07-12",
-        )
+        ):
+            self.assertIn("Gurban Bayrami", self.holidays[dt])
 
     def test_observed_days(self):
         observed_holidays = (
@@ -141,8 +146,8 @@ def test_observed_days(self):
             "2022-07-11",
             "2022-07-12",
         )
-        self.assertHoliday(Azerbaijan(observed=True), observed_holidays)
-        self.assertNoHoliday(Azerbaijan(observed=False), observed_holidays)
+        self.assertHoliday(observed_holidays)
+        self.assertNoNonObservedHoliday(observed_holidays)
 
     def test_2020(self):
         self.assertHolidayDates(
diff --git a/tests/countries/test_bolivia.py b/tests/countries/test_bolivia.py
index d5ce1ab85..854e6a222 100644
--- a/tests/countries/test_bolivia.py
+++ b/tests/countries/test_bolivia.py
@@ -15,9 +15,9 @@
 
 
 class TestBO(TestCase):
-    def setUp(self):
-        self.holidays = Bolivia()
-        self.holidays_no_observed = Bolivia(observed=False)
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Bolivia)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Bolivia, BO, BOL)
@@ -35,7 +35,7 @@ def test_new_years(self):
             "2034-01-02",
         )
         self.assertHolidaysName("Año Nuevo (Observed)", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_plurinational_state_foundation_day(self):
         name = "Nacimiento del Estado Plurinacional de Bolivia"
@@ -128,7 +128,7 @@ def test_labor_day(self):
             "2033-05-02",
         )
         self.assertHolidaysName(name, dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_chuquisaca_day(self):
         name = "Día del departamento de Chuquisaca"
@@ -170,7 +170,7 @@ def test_andean_new_year(self):
             "2043-06-22",
         )
         self.assertHolidaysName("Año Nuevo Andino (Observed)", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_la_paz_day(self):
         name = "Día del departamento de La Paz"
@@ -195,7 +195,7 @@ def test_independence_day(self):
             "2028-08-07",
         )
         self.assertHolidaysName("Día de la Patria (Observed)", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_cochabamba_day(self):
         name = "Día del departamento de Cochabamba"
@@ -239,7 +239,7 @@ def test_all_souls_day(self):
             "2036-11-03",
         )
         self.assertHolidaysName("Todos Santos (Observed)", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_potosi_day(self):
         name = "Día del departamento de Potosí"
@@ -273,4 +273,4 @@ def test_christmas_day(self):
             "2033-12-26",
         )
         self.assertHolidaysName("Navidad (Observed)", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
diff --git a/tests/countries/test_bosnia_and_herzegovina.py b/tests/countries/test_bosnia_and_herzegovina.py
index c6dd87342..868830ad5 100644
--- a/tests/countries/test_bosnia_and_herzegovina.py
+++ b/tests/countries/test_bosnia_and_herzegovina.py
@@ -15,12 +15,17 @@
 from tests.common import TestCase
 
 
-class TestBA(TestCase):
+class TestBosniaAndHerzegovina(TestCase):
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(BosniaAndHerzegovina)
+
     def setUp(self):
-        self.holidays = BosniaAndHerzegovina(observed=False)
+        super().setUp()
+
+        self.bd_holidays = BosniaAndHerzegovina(subdiv="BD")
         self.rs_holidays = BosniaAndHerzegovina(subdiv="RS")
         self.fbih_holidays = BosniaAndHerzegovina(subdiv="FBiH")
-        self.bd_holidays = BosniaAndHerzegovina(subdiv="BD")
 
     def test_country_aliases(self):
         self.assertCountryAliases(BosniaAndHerzegovina, BA, BIH)
@@ -44,10 +49,10 @@ def test_new_years(self):
         self.assertHolidaysName(name, self.fbih_holidays, dt)
         self.assertHolidaysName(name, self.bd_holidays, dt)
         self.assertNoHoliday(dt)
-        self.assertNoHoliday(
+        self.assertNoNonObservedHoliday(
             BosniaAndHerzegovina(subdiv="FBiH", observed=False), dt
         )
-        self.assertNoHoliday(
+        self.assertNoNonObservedHoliday(
             BosniaAndHerzegovina(subdiv="BD", observed=False), dt
         )
 
@@ -182,7 +187,7 @@ def test_labor_day(self):
             name,
             (f"{year}-05-02" for year in range(2000, 2022)),
         )
-        self.assertIn(name, self.holidays.get("2022-05-02"))
+        self.assertIn(name, self.holidays_non_observed.get("2022-05-02"))
         self.assertHolidaysName(
             name,
             (f"{year}-05-02" for year in range(2023, 2030)),
@@ -194,8 +199,8 @@ def test_labor_day(self):
             "2016-05-03",
             "2022-05-03",
         )
-        self.assertHolidaysName(name, BosniaAndHerzegovina(observed=True), dt)
-        self.assertNoHoliday(dt)
+        self.assertHolidaysName(name, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_victory_day(self):
         name = "Dan pobjede nad fašizmom"
@@ -277,7 +282,8 @@ def test_statehood_day(self):
     def test_catholic_christmas(self):
         for year in range(2010, 2025):
             self.assertEqual(
-                self.holidays.get(f"{year}-12-25"), "Božić (Katolički)"
+                self.holidays_non_observed.get(f"{year}-12-25"),
+                "Božić (Katolički)",
             )
         name = "Badnji dan (Katolički)"
         dt = (f"{year}-12-24" for year in range(2000, 2030))
diff --git a/tests/countries/test_botswana.py b/tests/countries/test_botswana.py
index 6ac57757e..6627445b8 100644
--- a/tests/countries/test_botswana.py
+++ b/tests/countries/test_botswana.py
@@ -14,9 +14,9 @@
 
 
 class TestBotswana(TestCase):
-    def setUp(self):
-        self.holidays = Botswana()
-        self.holidays_no_observed = Botswana(observed=False)
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Botswana)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Botswana, BW, BWA)
@@ -39,7 +39,7 @@ def test_new_years(self):
             "2023-01-03",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_easter(self):
         dt = (
@@ -53,7 +53,7 @@ def test_easter(self):
             "2022-05-26",
         )
         self.assertHoliday(dt)
-        self.assertHoliday(self.holidays_no_observed, dt)
+        self.assertNonObservedHoliday(dt)
 
     def test_labour_day(self):
         self.assertHoliday(f"{year}-05-01" for year in range(1966, 2050))
@@ -63,7 +63,7 @@ def test_labour_day(self):
             "2022-05-02",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
         dt = (
             "2021-05-03",
@@ -71,7 +71,7 @@ def test_labour_day(self):
             "2032-05-03",
         )
         self.assertHolidaysName("Labour Day Holiday", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_presidents_day(self):
         self.assertHoliday(
@@ -96,7 +96,7 @@ def test_botswana_day(self):
             "2023-10-02",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_christmas_day(self):
         for year in range(1966, 2050):
@@ -110,7 +110,7 @@ def test_christmas_day(self):
             "2022-12-27",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
         dt = (
             "2020-12-28",
@@ -118,7 +118,7 @@ def test_christmas_day(self):
             "2037-12-28",
         )
         self.assertHolidaysName("Boxing Day Holiday", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_2021(self):
         self.assertHolidayDates(
diff --git a/tests/countries/test_brazil.py b/tests/countries/test_brazil.py
index 29cb2fcb7..f69858bab 100644
--- a/tests/countries/test_brazil.py
+++ b/tests/countries/test_brazil.py
@@ -47,13 +47,15 @@ def test_BR_holidays(self):
         )
         self.assertIn("2018-10-12", self.holidays)
         self.assertEqual(
-            self.holidays[date(2018, 10, 12)], "Nossa Senhora Aparecida"
+            self.holidays[date(2018, 10, 12)],
+            "Nossa Senhora Aparecida",
         )
         self.assertIn("2018-11-02", self.holidays)
         self.assertEqual(self.holidays[date(2018, 11, 2)], "Finados")
         self.assertIn("2018-11-15", self.holidays)
         self.assertEqual(
-            self.holidays[date(2018, 11, 15)], "Proclamação da República"
+            self.holidays[date(2018, 11, 15)],
+            "Proclamação da República",
         )
         self.assertIn("2018-12-25", self.holidays)
         self.assertEqual(self.holidays[date(2018, 12, 25)], "Natal")
diff --git a/tests/countries/test_burundi.py b/tests/countries/test_burundi.py
index b72815d00..014ba03c6 100644
--- a/tests/countries/test_burundi.py
+++ b/tests/countries/test_burundi.py
@@ -14,8 +14,9 @@
 
 
 class TestBurundi(TestCase):
-    def setUp(self):
-        self.holidays = Burundi()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Burundi)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Burundi, BI, BDI)
@@ -200,4 +201,4 @@ def test_observed(self):
             "2024-06-17",
         )
         self.assertHoliday(observed_holidays)
-        self.assertNoHoliday(Burundi(observed=False), observed_holidays)
+        self.assertNoNonObservedHoliday(observed_holidays)
diff --git a/tests/countries/test_canada.py b/tests/countries/test_canada.py
index 162ba0b51..471a465c6 100644
--- a/tests/countries/test_canada.py
+++ b/tests/countries/test_canada.py
@@ -392,12 +392,14 @@ def test_christmas_day(self):
             self.assertNotIn(dt + td(days=-1), self.holidays)
         self.assertNotIn(date(2010, 12, 27), self.holidays)
         self.assertNotEqual(
-            self.holidays[date(2011, 12, 26)], "Christmas Day (Observed)"
+            self.holidays[date(2011, 12, 26)],
+            "Christmas Day (Observed)",
         )
         self.holidays.observed = True
         self.assertIn(date(2010, 12, 27), self.holidays)
         self.assertEqual(
-            self.holidays[date(2011, 12, 27)], "Christmas Day (Observed)"
+            self.holidays[date(2011, 12, 27)],
+            "Christmas Day (Observed)",
         )
 
     def test_boxing_day(self):
diff --git a/tests/countries/test_chile.py b/tests/countries/test_chile.py
index a8ba1244b..44a2f9a6b 100644
--- a/tests/countries/test_chile.py
+++ b/tests/countries/test_chile.py
@@ -14,8 +14,12 @@
 
 
 class TestChile(TestCase):
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Chile)
+
     def setUp(self):
-        self.holidays = Chile()
+        super().setUp()
         self.holidays_ap = Chile(subdiv="AP")
         self.holidays_nb = Chile(subdiv="NB")
 
@@ -67,15 +71,9 @@ def test_ascension(self):
             "1950-05-18",
             "1967-05-04",
         )
-        self.assertHolidayName(
-            "Ascensión del Señor [Ascension of Jesus]",
-            Chile(years=range(1915, 1968)),
-        )
-
-        self.assertNoHolidayName(
-            "Ascensión del Señor [Ascension of Jesus]",
-            Chile(years=range(1968, 2050)),
-        )
+        name = "Ascensión del Señor"
+        self.assertHolidayName(name, Chile(years=range(1915, 1968)))
+        self.assertNoHolidayName(name, Chile(years=range(1968, 2050)))
 
     def test_corpus_christi(self):
         self.assertHoliday(
@@ -88,18 +86,10 @@ def test_corpus_christi(self):
             "2000-06-19",
             "2006-06-12",
         )
-        self.assertHolidayName(
-            "Corpus Christi [Corpus Christi]",
-            Chile(years=range(1915, 1968)),
-        )
-        self.assertNoHolidayName(
-            "Corpus Christi [Corpus Christi]",
-            Chile(years=range(1968, 1987)),
-        )
-        self.assertHolidayName(
-            "Corpus Christi [Corpus Christi]",
-            Chile(years=range(1987, 2006)),
-        )
+        name = "Corpus Christi"
+        self.assertHolidayName(name, Chile(years=range(1915, 1968)))
+        self.assertNoHolidayName(name, Chile(years=range(1968, 1987)))
+        self.assertHolidayName(name, Chile(years=range(1987, 2006)))
 
     def test_labour_day(self):
         self.assertHoliday(f"{year}-05-01" for year in range(1932, 2050))
@@ -187,7 +177,6 @@ def test_saint_peter_and_paul(self):
         )
 
     def test_virgin_of_carmen(self):
-        # Day of Virgin of Carmen started after 2006
         self.assertHoliday(f"{year}-07-16" for year in range(2007, 2050))
         self.assertNoHoliday(f"{year}-07-16" for year in range(1915, 2007))
 
@@ -200,14 +189,9 @@ def test_national_liberation(self):
             "1980-09-11",
             "1999-09-11",
         )
-        self.assertNoHolidayName(
-            "Día de la Liberación Nacional",
-            Chile(years=range(1915, 1981)),
-        )
-        self.assertNoHolidayName(
-            "Día de la Liberación Nacional",
-            Chile(years=range(1999, 2050)),
-        )
+        name = "Día de la Liberación Nacional"
+        self.assertNoHolidayName(name, Chile(years=range(1915, 1981)))
+        self.assertNoHolidayName(name, Chile(years=range(1999, 2050)))
 
     def test_national_unity(self):
         self.assertHoliday(
@@ -240,18 +224,12 @@ def test_independence_holidays(self):
         self.assertHoliday(f"{year}-09-20" for year in range(1932, 1945))
 
     def test_columbus_day(self):
-        for year in range(1922, 2000):
-            if year != 1973:
-                self.assertHoliday(f"{year}-10-12")
-                self.assertHolidayName(
-                    "Día de la Raza [Columbus day]",
-                    Chile(years=year),
-                )
-            else:
-                self.assertNoHolidayName(
-                    "Día de la Raza [Columbus day]",
-                    Chile(years=year),
-                )
+        years = set(range(1922, 2000)).difference({1973})
+        name = "Día de la Raza"
+        for year in years:
+            self.assertHoliday(f"{year}-10-12")
+            self.assertHolidayName(name, Chile(years=year))
+        self.assertNoHolidayName(name, Chile(years=1973))
 
         self.assertHoliday(
             "2000-10-09",
@@ -266,13 +244,8 @@ def test_columbus_day(self):
         )
 
         self.assertHolidayName(
-            "Día del Respeto a la Diversidad",
-            Chile(years=range(2000, 2020)),
-        )
-
-        self.assertHolidayName(
-            "Día del Descubrimiento de dos Mundos",
-            Chile(years=range(2020, 2050)),
+            "Día del Encuentro de dos Mundos",
+            Chile(years=range(2000, 2050)),
         )
 
     def test_reformation_day(self):
@@ -397,3 +370,41 @@ def test_2079(self):
         self.assertHoliday(
             "2079-06-20",
         )
+
+    def test_l10n_default(self):
+        def run_tests(languages):
+            for language in languages:
+                cl = Chile(language=language)
+                self.assertEqual(cl["2022-01-01"], "Año Nuevo")
+                self.assertEqual(cl["2022-12-25"], "Navidad")
+
+        run_tests((Chile.default_language, None, "invalid"))
+
+        self.set_language("en_US")
+        run_tests((Chile.default_language,))
+
+    def test_l10n_en_us(self):
+        en_us = "en_US"
+
+        cl = Chile(language=en_us)
+        self.assertEqual(cl["2022-01-01"], "New Year's Day")
+        self.assertEqual(cl["2022-12-25"], "Christmas")
+
+        self.set_language(en_us)
+        for language in (None, en_us, "invalid"):
+            cl = Chile(language=language)
+            self.assertEqual(cl["2022-01-01"], "New Year's Day")
+            self.assertEqual(cl["2022-12-25"], "Christmas")
+
+    def test_l10n_uk(self):
+        uk = "uk"
+
+        cl = Chile(language=uk)
+        self.assertEqual(cl["2022-01-01"], "Новий рік")
+        self.assertEqual(cl["2022-12-25"], "Різдво Христове")
+
+        self.set_language(uk)
+        for language in (None, uk, "invalid"):
+            cl = Chile(language=language)
+            self.assertEqual(cl["2022-01-01"], "Новий рік")
+            self.assertEqual(cl["2022-12-25"], "Різдво Христове")
diff --git a/tests/countries/test_colombia.py b/tests/countries/test_colombia.py
index 27c16ca1b..c244ccdad 100644
--- a/tests/countries/test_colombia.py
+++ b/tests/countries/test_colombia.py
@@ -9,309 +9,309 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import unittest
-from datetime import date
-from datetime import timedelta as td
+from holidays.countries.colombia import Colombia, CO, COL
+from tests.common import TestCase
 
-import holidays
-from holidays.constants import APR, AUG, DEC, JAN, JUL, JUN, MAR, MAY, NOV, OCT
 
+class TestColombia(TestCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Colombia)
 
-class TestCO(unittest.TestCase):
-    def setUp(self):
-        self.holidays = holidays.CO(observed=True)
-
-    def _check_all_dates(self, year, expected_holidays):
-        start_date = date(year, 1, 1)
-        end_date = date(year, 12, 31)
-        delta = td(days=+1)
-
-        while start_date <= end_date:
-            if start_date in expected_holidays:
-                self.assertIn(start_date, self.holidays)
-            else:
-                self.assertNotIn(start_date, self.holidays)
-            start_date += delta
+    def test_country_aliases(self):
+        self.assertCountryAliases(Colombia, CO, COL)
 
     def test_2016(self):
         # https://www.officeholidays.com/countries/colombia/2016
-        year = 2016
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 11),
-            date(year, MAR, 21),
-            date(year, MAR, 24),
-            date(year, MAR, 25),
-            date(year, MAY, 1),
-            date(year, MAY, 9),
-            date(year, MAY, 30),
-            date(year, JUN, 6),
-            date(year, JUL, 4),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 15),
-            date(year, OCT, 17),
-            date(year, NOV, 7),
-            date(year, NOV, 14),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "2016-01-01",
+            "2016-01-11",
+            "2016-03-21",
+            "2016-03-24",
+            "2016-03-25",
+            "2016-05-01",
+            "2016-05-09",
+            "2016-05-30",
+            "2016-06-06",
+            "2016-07-04",
+            "2016-07-20",
+            "2016-08-07",
+            "2016-08-15",
+            "2016-10-17",
+            "2016-11-07",
+            "2016-11-14",
+            "2016-12-08",
+            "2016-12-25",
+        )
 
     def test_2017(self):
         # https://www.officeholidays.com/countries/colombia/2017
-        year = 2017
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 9),
-            date(year, MAR, 20),
-            date(year, APR, 13),
-            date(year, APR, 14),
-            date(year, MAY, 1),
-            date(year, MAY, 29),
-            date(year, JUN, 19),
-            date(year, JUN, 26),
-            date(year, JUL, 3),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 21),
-            date(year, OCT, 16),
-            date(year, NOV, 6),
-            date(year, NOV, 13),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "2017-01-01",
+            "2017-01-09",
+            "2017-03-20",
+            "2017-04-13",
+            "2017-04-14",
+            "2017-05-01",
+            "2017-05-29",
+            "2017-06-19",
+            "2017-06-26",
+            "2017-07-03",
+            "2017-07-20",
+            "2017-08-07",
+            "2017-08-21",
+            "2017-10-16",
+            "2017-11-06",
+            "2017-11-13",
+            "2017-12-08",
+            "2017-12-25",
+        )
 
     def test_2018(self):
         # https://publicholidays.co/2018-dates/
-        year = 2018
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 8),
-            date(year, MAR, 19),
-            date(year, MAR, 29),
-            date(year, MAR, 30),
-            date(year, MAY, 1),
-            date(year, MAY, 14),
-            date(year, JUN, 4),
-            date(year, JUN, 11),
-            date(year, JUL, 2),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 20),
-            date(year, OCT, 15),
-            date(year, NOV, 5),
-            date(year, NOV, 12),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "2018-01-01",
+            "2018-01-08",
+            "2018-03-19",
+            "2018-03-29",
+            "2018-03-30",
+            "2018-05-01",
+            "2018-05-14",
+            "2018-06-04",
+            "2018-06-11",
+            "2018-07-02",
+            "2018-07-20",
+            "2018-08-07",
+            "2018-08-20",
+            "2018-10-15",
+            "2018-11-05",
+            "2018-11-12",
+            "2018-12-08",
+            "2018-12-25",
+        )
 
     def test_2019(self):
         # https://www.officeholidays.com/countries/colombia/2019
-        year = 2019
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 7),
-            date(year, MAR, 25),
-            date(year, APR, 18),
-            date(year, APR, 19),
-            date(year, MAY, 1),
-            date(year, JUN, 3),
-            date(year, JUN, 24),
-            date(year, JUL, 1),
-            date(year, JUL, 1),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 19),
-            date(year, OCT, 14),
-            date(year, NOV, 4),
-            date(year, NOV, 11),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "2019-01-01",
+            "2019-01-07",
+            "2019-03-25",
+            "2019-04-18",
+            "2019-04-19",
+            "2019-05-01",
+            "2019-06-03",
+            "2019-06-24",
+            "2019-07-01",
+            "2019-07-20",
+            "2019-08-07",
+            "2019-08-19",
+            "2019-10-14",
+            "2019-11-04",
+            "2019-11-11",
+            "2019-12-08",
+            "2019-12-25",
+        )
 
     def test_2020(self):
         # https://www.officeholidays.com/countries/colombia/2020
-        year = 2020
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 6),
-            date(year, MAR, 23),
-            date(year, APR, 9),
-            date(year, APR, 10),
-            date(year, MAY, 1),
-            date(year, MAY, 25),
-            date(year, JUN, 15),
-            date(year, JUN, 22),
-            date(year, JUN, 29),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 17),
-            date(year, OCT, 12),
-            date(year, NOV, 2),
-            date(year, NOV, 16),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "2020-01-01",
+            "2020-01-06",
+            "2020-03-23",
+            "2020-04-09",
+            "2020-04-10",
+            "2020-05-01",
+            "2020-05-25",
+            "2020-06-15",
+            "2020-06-22",
+            "2020-06-29",
+            "2020-07-20",
+            "2020-08-07",
+            "2020-08-17",
+            "2020-10-12",
+            "2020-11-02",
+            "2020-11-16",
+            "2020-12-08",
+            "2020-12-25",
+        )
 
     def test_2021(self):
         # https://www.officeholidays.com/countries/colombia/2021
-        year = 2021
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 11),
-            date(year, MAR, 22),
-            date(year, APR, 1),
-            date(year, APR, 2),
-            date(year, MAY, 1),
-            date(year, MAY, 17),
-            date(year, JUN, 7),
-            date(year, JUN, 14),
-            date(year, JUL, 5),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 16),
-            date(year, OCT, 18),
-            date(year, NOV, 1),
-            date(year, NOV, 15),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "2021-01-01",
+            "2021-01-11",
+            "2021-03-22",
+            "2021-04-01",
+            "2021-04-02",
+            "2021-05-01",
+            "2021-05-17",
+            "2021-06-07",
+            "2021-06-14",
+            "2021-07-05",
+            "2021-07-20",
+            "2021-08-07",
+            "2021-08-16",
+            "2021-10-18",
+            "2021-11-01",
+            "2021-11-15",
+            "2021-12-08",
+            "2021-12-25",
+        )
 
     def test_2022(self):
         # https://www.officeholidays.com/countries/colombia/2022
-        year = 2022
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 10),
-            date(year, MAR, 21),
-            date(year, APR, 14),
-            date(year, APR, 15),
-            date(year, MAY, 1),
-            date(year, MAY, 30),
-            date(year, JUN, 20),
-            date(year, JUN, 27),
-            date(year, JUL, 4),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 15),
-            date(year, OCT, 17),
-            date(year, NOV, 7),
-            date(year, NOV, 14),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "2022-01-01",
+            "2022-01-10",
+            "2022-03-21",
+            "2022-04-14",
+            "2022-04-15",
+            "2022-05-01",
+            "2022-05-30",
+            "2022-06-20",
+            "2022-06-27",
+            "2022-07-04",
+            "2022-07-20",
+            "2022-08-07",
+            "2022-08-15",
+            "2022-10-17",
+            "2022-11-07",
+            "2022-11-14",
+            "2022-12-08",
+            "2022-12-25",
+        )
 
     def test_2023(self):
         # https://publicholidays.co/2023-dates/
-        year = 2023
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 9),
-            date(year, MAR, 20),
-            date(year, APR, 6),
-            date(year, APR, 7),
-            date(year, MAY, 1),
-            date(year, MAY, 22),
-            date(year, JUN, 12),
-            date(year, JUN, 19),
-            date(year, JUL, 3),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 21),
-            date(year, OCT, 16),
-            date(year, NOV, 6),
-            date(year, NOV, 13),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "2023-01-01",
+            "2023-01-09",
+            "2023-03-20",
+            "2023-04-06",
+            "2023-04-07",
+            "2023-05-01",
+            "2023-05-22",
+            "2023-06-12",
+            "2023-06-19",
+            "2023-07-03",
+            "2023-07-20",
+            "2023-08-07",
+            "2023-08-21",
+            "2023-10-16",
+            "2023-11-06",
+            "2023-11-13",
+            "2023-12-08",
+            "2023-12-25",
+        )
 
     def test_1984(self):
-        year = 1984
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 9),
-            date(year, MAR, 19),
-            date(year, APR, 19),
-            date(year, APR, 20),
-            date(year, MAY, 1),
-            date(year, JUN, 4),
-            date(year, JUN, 25),
-            date(year, JUL, 2),
-            date(year, JUL, 2),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 20),
-            date(year, OCT, 15),
-            date(year, NOV, 5),
-            date(year, NOV, 12),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "1984-01-01",
+            "1984-01-09",
+            "1984-03-19",
+            "1984-04-19",
+            "1984-04-20",
+            "1984-05-01",
+            "1984-06-04",
+            "1984-06-25",
+            "1984-07-02",
+            "1984-07-20",
+            "1984-08-07",
+            "1984-08-20",
+            "1984-10-15",
+            "1984-11-05",
+            "1984-11-12",
+            "1984-12-08",
+            "1984-12-25",
+        )
 
     def test_1983(self):
-        year = 1983
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 6),
-            date(year, MAR, 19),
-            date(year, MAR, 31),
-            date(year, APR, 1),
-            date(year, MAY, 1),
-            date(year, MAY, 12),
-            date(year, JUN, 2),
-            date(year, JUN, 29),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 15),
-            date(year, OCT, 12),
-            date(year, NOV, 1),
-            date(year, NOV, 11),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "1983-01-01",
+            "1983-01-06",
+            "1983-03-19",
+            "1983-03-31",
+            "1983-04-01",
+            "1983-05-01",
+            "1983-05-12",
+            "1983-06-02",
+            "1983-06-29",
+            "1983-07-20",
+            "1983-08-07",
+            "1983-08-15",
+            "1983-10-12",
+            "1983-11-01",
+            "1983-11-11",
+            "1983-12-08",
+            "1983-12-25",
+        )
 
     def test_1951(self):
-        year = 1951
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, JAN, 6),
-            date(year, MAR, 19),
-            date(year, MAR, 22),
-            date(year, MAR, 23),
-            date(year, MAY, 1),
-            date(year, MAY, 3),
-            date(year, MAY, 24),
-            date(year, JUN, 29),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, AUG, 15),
-            date(year, OCT, 12),
-            date(year, NOV, 1),
-            date(year, NOV, 11),
-            date(year, DEC, 8),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "1951-01-01",
+            "1951-01-06",
+            "1951-03-19",
+            "1951-03-22",
+            "1951-03-23",
+            "1951-05-01",
+            "1951-05-03",
+            "1951-05-24",
+            "1951-06-29",
+            "1951-07-20",
+            "1951-08-07",
+            "1951-08-15",
+            "1951-10-12",
+            "1951-11-01",
+            "1951-11-11",
+            "1951-12-08",
+            "1951-12-25",
+        )
 
     def test_1950(self):
-        year = 1950
-        expected_holidays = {
-            date(year, JAN, 1),
-            date(year, MAY, 1),
-            date(year, JUL, 20),
-            date(year, AUG, 7),
-            date(year, OCT, 12),
-            date(year, NOV, 11),
-            date(year, DEC, 25),
-        }
-        self._check_all_dates(year, expected_holidays)
+        self.assertHolidayDates(
+            "1950-01-01",
+            "1950-05-01",
+            "1950-07-20",
+            "1950-08-07",
+            "1950-10-12",
+            "1950-11-11",
+            "1950-12-25",
+        )
+
+    def test_l10n_default(self):
+        def run_tests(languages):
+            for language in languages:
+                co = Colombia(language=language)
+                self.assertEqual(co["2022-01-01"], "Año Nuevo")
+                self.assertEqual(co["2022-12-25"], "Navidad")
+
+        run_tests((Colombia.default_language, None, "invalid"))
+
+        self.set_language("en_US")
+        run_tests((Colombia.default_language,))
+
+    def test_l10n_en_us(self):
+        en_us = "en_US"
+
+        co = Colombia(language=en_us)
+        self.assertEqual(co["2018-01-01"], "New Year's Day")
+        self.assertEqual(co["2022-12-25"], "Christmas")
+
+        self.set_language(en_us)
+        for language in (None, en_us, "invalid"):
+            co = Colombia(language=language)
+            self.assertEqual(co["2018-01-01"], "New Year's Day")
+            self.assertEqual(co["2022-12-25"], "Christmas")
+
+    def test_l10n_uk(self):
+        uk = "uk"
+
+        co = Colombia(language=uk)
+        self.assertEqual(co["2022-01-01"], "Новий рік")
+        self.assertEqual(co["2022-12-25"], "Різдво Христове")
+
+        self.set_language(uk)
+        for language in (None, uk, "invalid"):
+            co = Colombia(language=language)
+            self.assertEqual(co["2022-01-01"], "Новий рік")
+            self.assertEqual(co["2022-12-25"], "Різдво Христове")
diff --git a/tests/countries/test_eswatini.py b/tests/countries/test_eswatini.py
index 8c91263b5..8fd8e602c 100644
--- a/tests/countries/test_eswatini.py
+++ b/tests/countries/test_eswatini.py
@@ -17,8 +17,9 @@
 
 
 class TestEswatini(TestCase):
-    def setUp(self):
-        self.holidays = Eswatini()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Eswatini)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Eswatini, SZ, SZW)
@@ -113,7 +114,7 @@ def test_observed(self):
             "2027-12-27",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Eswatini(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_swaziland_deprecation_warning(self):
         warnings.simplefilter("default")
diff --git a/tests/countries/test_greece.py b/tests/countries/test_greece.py
index bf453096e..93c1b87ac 100644
--- a/tests/countries/test_greece.py
+++ b/tests/countries/test_greece.py
@@ -37,9 +37,9 @@ def test_fixed_holidays(self):
                 (date(y, 12, 26), "Επόμενη ημέρα των Χριστουγέννων"),
             )
 
-        for d, dstr in fdays:
-            self.assertIn(d, self.holidays)
-            self.assertIn(dstr, self.holidays[d])
+            for d, dstr in fdays:
+                self.assertIn(d, self.holidays)
+                self.assertIn(dstr, self.holidays[d])
 
     def test_gr_clean_monday(self):
         checkdates = (
diff --git a/tests/countries/test_hongkong.py b/tests/countries/test_hongkong.py
index 02c1d8c72..94fd2aec9 100644
--- a/tests/countries/test_hongkong.py
+++ b/tests/countries/test_hongkong.py
@@ -9,27 +9,33 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import unittest
 from datetime import date
 
-import holidays
+from holidays.countries.hongkong import HongKong, HK, HKG
+from tests.common import TestCase
 
 
-class TestHongKong(unittest.TestCase):
-    def setUp(self):
-        self.holidays = holidays.HK()
+class TestHongKong(TestCase):
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(HongKong)
+
+    def test_country_aliases(self):
+        self.assertCountryAliases(HongKong, HK, HKG)
 
     def test_common(self):
-        holidays_no_observed = holidays.HK(observed=False)
-        self.assertEqual(
-            holidays_no_observed[date(2019, 1, 1)], "The first day of January"
+        self.assertNonObservedHoliday("2019-01-01")
+        self.assertNonObservedHolidaysName(
+            "The first day of January",
+            "2019-01-01",
         )
+
         self.assertEqual(
             self.holidays[date(2015, 9, 3)],
             "The 70th anniversary day of the victory of the Chinese "
             "people's war of resistance against Japanese aggression",
         )
-        self.assertEqual(len(holidays.HK(years=1945)), 0)
+        self.assertEqual(len(HongKong(years=1945)), 0)
 
     def test_first_day_of_january(self):
         exception_years = (2006, 2012, 2017, 2023)
@@ -41,7 +47,8 @@ def test_first_day_of_january(self):
                 )
             else:
                 self.assertEqual(
-                    self.holidays[date(year, 1, 1)], "The first day of January"
+                    self.holidays[date(year, 1, 1)],
+                    "The first day of January",
                 )
 
     def test_lunar_new_year(self):
@@ -67,7 +74,8 @@ def test_lunar_new_year(self):
             (2022, 2, 1),
         ]:
             self.assertEqual(
-                self.holidays[date(year, month, day)], "Lunar New Year's Day"
+                self.holidays[date(year, month, day)],
+                "Lunar New Year's Day",
             )
 
         for year, month, day in [
@@ -148,7 +156,8 @@ def test_ching_ming_festival(self):
             (2023, 4, 5),
         ]:
             self.assertEqual(
-                self.holidays[date(year, month, day)], "Ching Ming Festival"
+                self.holidays[date(year, month, day)],
+                "Ching Ming Festival",
             )
 
         for year, month, day in [(2010, 4, 6), (2015, 4, 6), (2021, 4, 5)]:
@@ -289,7 +298,8 @@ def test_labour_day(self):
 
         for year in (2011, 2016, 2022):
             self.assertEqual(
-                self.holidays[date(year, 5, 2)], "The day following Labour Day"
+                self.holidays[date(year, 5, 2)],
+                "The day following Labour Day",
             )
 
         self.assertNotIn(date(1997, 5, 1), self.holidays)
@@ -316,7 +326,8 @@ def test_tuen_ng_festival(self):
             (2023, 6, 22),
         ]:
             self.assertEqual(
-                self.holidays[date(year, month, day)], "Tuen Ng Festival"
+                self.holidays[date(year, month, day)],
+                "Tuen Ng Festival",
             )
 
         self.assertEqual(
diff --git a/tests/countries/test_indonesia.py b/tests/countries/test_indonesia.py
index 981b71900..4f043798b 100644
--- a/tests/countries/test_indonesia.py
+++ b/tests/countries/test_indonesia.py
@@ -44,7 +44,8 @@ def test_lunar_new_year(self):
             (2022, 2, 1),
         ):
             self.assertEqual(
-                self.holidays[date(year, month, day)], "Tahun Baru Imlek"
+                self.holidays[date(year, month, day)],
+                "Tahun Baru Imlek",
             )
 
     def test_day_of_silence(self):
@@ -57,7 +58,8 @@ def test_day_of_silence(self):
             (2022, 3, 3),
         ):
             self.assertEqual(
-                self.holidays[date(year, month, day)], "Hari Suci Nyepi"
+                self.holidays[date(year, month, day)],
+                "Hari Suci Nyepi",
             )
 
         self.assertFalse(Indonesia(years=1982).get_named("Hari Suci Nyepi"))
diff --git a/tests/countries/test_ireland.py b/tests/countries/test_ireland.py
index 0d052fa57..4a447255a 100644
--- a/tests/countries/test_ireland.py
+++ b/tests/countries/test_ireland.py
@@ -33,6 +33,24 @@ def test_2020(self):
         self.assertIn("2020-12-26", self.holidays)  # Boxing Day
         self.assertIn("2020-12-28", self.holidays)  # Boxing Day (Observed)
 
+    def test_st_brigids_day(self):
+        # St. Brigid's Day
+        for dt in (
+            date(2023, 2, 6),
+            date(2024, 2, 5),
+            date(2025, 2, 3),
+            date(2026, 2, 2),
+            date(2027, 2, 1),
+            date(2028, 2, 7),
+            date(2029, 2, 5),
+            date(2030, 2, 1),
+            date(2031, 2, 3),
+            date(2032, 2, 2),
+        ):
+            self.assertIn(dt, self.holidays)
+            self.assertNotIn(dt + td(days=-1), self.holidays)
+            self.assertNotIn(dt + td(days=+1), self.holidays)
+
     def test_may_day(self):
         # Specific Ireland "May Day"
         for dt in [
diff --git a/tests/countries/test_jamaica.py b/tests/countries/test_jamaica.py
index 949bf4f52..7f9e9a0d2 100644
--- a/tests/countries/test_jamaica.py
+++ b/tests/countries/test_jamaica.py
@@ -14,9 +14,9 @@
 
 
 class TestJamaica(TestCase):
-    def setUp(self):
-        self.holidays = Jamaica()
-        self.holidays_no_observed = Jamaica(observed=False)
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Jamaica)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Jamaica, JM, JAM)
@@ -31,7 +31,7 @@ def test_new_years_day(self):
             "2023-01-02",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_labour_day(self):
         self.assertHoliday(f"{year}-05-23" for year in range(1950, 2050))
@@ -48,7 +48,7 @@ def test_labour_day(self):
             "2027-05-24",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_emancipation_day(self):
         self.assertHoliday(f"{year}-08-01" for year in range(1998, 2050))
@@ -60,7 +60,7 @@ def test_emancipation_day(self):
             "2027-08-02",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
         self.assertNoHolidayName("Emancipation Day", Jamaica(years=1997))
 
     def test_independence_day(self):
@@ -73,7 +73,7 @@ def test_independence_day(self):
             "2028-08-07",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_national_heroes_day(self):
         self.assertHoliday(
@@ -99,7 +99,7 @@ def test_christmas_day(self):
             "2033-12-27",
         )
         self.assertHolidaysName("Christmas Day (Observed)", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_boxing_day(self):
         self.assertHoliday(f"{year}-12-26" for year in range(1950, 2050))
@@ -111,7 +111,7 @@ def test_boxing_day(self):
             "2032-12-27",
         )
         self.assertHolidaysName("Boxing Day (Observed)", dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_ash_wednesday(self):
         self.assertHoliday(
diff --git a/tests/countries/test_japan.py b/tests/countries/test_japan.py
index 329fa7932..166d22f72 100644
--- a/tests/countries/test_japan.py
+++ b/tests/countries/test_japan.py
@@ -578,7 +578,6 @@ def test_reiwa_emperor_holidays(self):
         self.assertIn(date(2019, 10, 22), self.holidays)
 
     def test_observed_holidays(self):
-        no_observed = Japan(observed=False)
         hol_list = (
             # 振替休日
             (1973, 4, 30),
@@ -721,8 +720,8 @@ def test_observed_holidays(self):
             (2037, 9, 22),
         )
         for dt in hol_list:
-            self.assertIn(date(*dt), self.holidays)
-            self.assertNotIn(date(*dt), no_observed)
+            self.assertHoliday(date(*dt))
+            self.assertNoNonObservedHoliday(date(*dt))
 
     def test_l10n_default(self):
         def run_tests(languages):
diff --git a/tests/countries/test_kazakhstan.py b/tests/countries/test_kazakhstan.py
index d88f36913..82f8f6859 100644
--- a/tests/countries/test_kazakhstan.py
+++ b/tests/countries/test_kazakhstan.py
@@ -14,8 +14,9 @@
 
 
 class TestKazakhstan(TestCase):
-    def setUp(self):
-        self.holidays = Kazakhstan()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Kazakhstan)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Kazakhstan, KZ, KAZ)
@@ -44,7 +45,7 @@ def test_nauryz(self):
                 f"{year}-03-21", f"{year}-03-22", f"{year}-03-23"
             )
         for year in range(2002, 2010):
-            self.assertNoHoliday(
+            self.assertNoNonObservedHoliday(
                 Kazakhstan(observed=False, years=year),
                 f"{year}-03-21",
                 f"{year}-03-23",
@@ -84,7 +85,7 @@ def test_independence_day(self):
         self.assertHoliday(f"{year}-12-17" for year in range(2002, 2022))
         self.assertNoHoliday(f"{year}-12-17" for year in range(1991, 2002))
         for year in range(2022, 2100):
-            self.assertNoHoliday(
+            self.assertNoNonObservedHoliday(
                 Kazakhstan(observed=False, years=year), f"{year}-12-17"
             )
 
@@ -155,7 +156,7 @@ def test_observed(self):
             "2022-05-10",
         )
         self.assertHoliday(observed_holidays)
-        self.assertNoHoliday(Kazakhstan(observed=False), observed_holidays)
+        self.assertNoNonObservedHoliday(observed_holidays)
 
     def test2020(self):
         self.assertHolidayDates(
diff --git a/tests/countries/test_kenya.py b/tests/countries/test_kenya.py
index bf2eed8e4..08bee91cc 100644
--- a/tests/countries/test_kenya.py
+++ b/tests/countries/test_kenya.py
@@ -14,8 +14,9 @@
 
 
 class TestKenya(TestCase):
-    def setUp(self):
-        self.holidays = Kenya()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Kenya)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Kenya, KE, KEN)
@@ -125,7 +126,7 @@ def test_observed(self):
             "2021-12-27",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Kenya(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_2019(self):
         self.assertHolidayDates(
diff --git a/tests/countries/test_malawi.py b/tests/countries/test_malawi.py
index 77c5217cd..048138012 100644
--- a/tests/countries/test_malawi.py
+++ b/tests/countries/test_malawi.py
@@ -14,8 +14,9 @@
 
 
 class TestMalawi(TestCase):
-    def setUp(self):
-        self.holidays = Malawi()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Malawi)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Malawi, MW, MWI)
@@ -109,4 +110,4 @@ def test_observed(self):
             "2021-12-28",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Malawi(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
diff --git a/tests/countries/test_malaysia.py b/tests/countries/test_malaysia.py
index afb4e4ddc..82e7eefeb 100644
--- a/tests/countries/test_malaysia.py
+++ b/tests/countries/test_malaysia.py
@@ -9,59 +9,51 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import unittest
 from datetime import date
 
-import holidays
 from holidays.constants import APR, AUG, DEC, FEB, JAN, JUL, JUN, MAR, MAY
 from holidays.constants import NOV, OCT, SEP
+from holidays.countries.malaysia import Malaysia, MY, MYS
+from tests.common import TestCase
 
 
-class TestMalaysia(unittest.TestCase):
+class TestMalaysia(TestCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Malaysia)
+
     def setUp(self):
-        self.holidays = holidays.Malaysia()
-        years = (
-            1970,
-            1985,
-            1990,
-            2001,
-            2010,
-            2014,
-            2015,
-            2018,
-            2019,
-            2020,
-            2021,
-            2022,
-            2023,
-        )
-        self.johor_holidays = holidays.Malaysia(years=years, subdiv="JHR")
-        self.kedah_holidays = holidays.Malaysia(years=years, subdiv="KDH")
-        self.kelantan_holidays = holidays.Malaysia(years=years, subdiv="KTN")
-        self.malacca_holidays = holidays.Malaysia(years=years, subdiv="MLK")
-        self.negeri_sembilan_holidays = holidays.Malaysia(
-            years=years,
-            subdiv="NSN",
-        )
-        self.pahang_holidays = holidays.Malaysia(years=years, subdiv="PHG")
-        self.perak_holidays = holidays.Malaysia(years=years, subdiv="PRK")
-        self.perlis_holidays = holidays.Malaysia(years=years, subdiv="PLS")
-        self.penang_holidays = holidays.Malaysia(years=years, subdiv="PNG")
-        self.sabah_holidays = holidays.Malaysia(years=years, subdiv="SBH")
-        self.sarawak_holidays = holidays.Malaysia(years=years, subdiv="SWK")
-        self.selangor_holidays = holidays.Malaysia(years=years, subdiv="SGR")
-        self.terengganu_holidays = holidays.Malaysia(years=years, subdiv="TRG")
-        self.kuala_lumpur_holidays = holidays.Malaysia(
-            years=years, subdiv="KUL"
-        )
-        self.labuan_holidays = holidays.Malaysia(years=years, subdiv="LBN")
-        self.putrajaya_holidays = holidays.Malaysia(years=years, subdiv="PJY")
+        super().setUp()
 
-    def test_Malaysia_Wikipedia(self):
+        years = range(2012, 2023)
+        self.jhr_holidays = Malaysia(years=years, subdiv="JHR")
+        self.kdh_holidays = Malaysia(years=years, subdiv="KDH")
+        self.ktn_holidays = Malaysia(years=years, subdiv="KTN")
+        self.mlk_holidays = Malaysia(years=years, subdiv="MLK")
+        self.nsn_holidays = Malaysia(years=years, subdiv="NSN")
+        self.phg_holidays = Malaysia(years=years, subdiv="PHG")
+        self.prk_holidays = Malaysia(years=years, subdiv="PRK")
+        self.pls_holidays = Malaysia(years=years, subdiv="PLS")
+        self.png_holidays = Malaysia(years=years, subdiv="PNG")
+        self.sbh_holidays = Malaysia(years=years, subdiv="SBH")
+        self.swk_holidays = Malaysia(years=years, subdiv="SWK")
+        self.sgr_holidays = Malaysia(years=years, subdiv="SGR")
+        self.trg_holidays = Malaysia(years=years, subdiv="TRG")
+        self.kul_holidays = Malaysia(years=years, subdiv="KUL")
+        self.lbn_holidays = Malaysia(years=years, subdiv="LBN")
+        self.pjy_holidays = Malaysia(years=years, subdiv="PJY")
+
+    def test_country_aliases(self):
+        self.assertCountryAliases(Malaysia, MY, MYS)
+        holidays1 = MY()
+        holidays2 = MYS()
+        self.assertEqual(list(holidays1), list(holidays2))
+
+    def test_malaysia_wikipedia(self):
         # reproduce table at
         # https://en.wikipedia.org/wiki/Public_holidays_in_Malaysia
         # as of 19-Sep-21
-        columns = [
+        columns = (
             "JHR",  # "Johor"
             "KDH",  # "Kedah"
             "KTN",  # "Kelantan"
@@ -78,1542 +70,1234 @@ def test_Malaysia_Wikipedia(self):
             "SWK",  # "Sarawak"
             "SGR",  # "Selangor"
             "TRG",  # "Terengganu"
-        ]
-        rows = {
-            date(2021, JAN, 1): [
-                0,
-                0,
-                0,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                0,
-                1,
-                1,
-                1,
-                1,
-                0,
-            ],
-            date(2021, JAN, 14): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, JAN, 28): [
-                1,
-                0,
-                0,
-                1,
-                0,
-                0,
-                1,
-                0,
-                1,
-                1,
-                0,
-                1,
-                0,
-                0,
-                1,
-                0,
-            ],
-            date(2021, FEB, 1): [
-                0,
-                0,
-                0,
-                1,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, FEB, 12): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, FEB, 13): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, FEB, 14): [
-                1,
-                1,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-            ],
-            date(2021, MAR, 4): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-            ],
-            date(2021, MAR, 11): [
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                1,
-            ],
-            date(2021, MAR, 23): [
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, APR, 2): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                1,
-                0,
-                0,
-            ],
-            date(2021, APR, 13): [
-                1,
-                1,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, APR, 15): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, APR, 26): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-            ],
-            date(2021, APR, 29): [
-                0,
-                0,
-                1,
-                1,
-                1,
-                0,
-                0,
-                1,
-                1,
-                1,
-                1,
-                1,
-                0,
-                0,
-                1,
-                1,
-            ],
-            date(2021, MAY, 1): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, MAY, 2): [
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-            ],
-            date(2021, MAY, 13): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, MAY, 14): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, MAY, 16): [
-                1,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, MAY, 22): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, MAY, 26): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, MAY, 30): [
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-            ],
-            date(2021, MAY, 31): [
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-            ],
-            date(2021, JUN, 1): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-            ],
-            date(2021, JUN, 2): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-            ],
-            date(2021, JUN, 7): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, JUN, 20): [
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, JUL, 7): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, JUL, 10): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, JUL, 17): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, JUL, 19): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-            ],
-            date(2021, JUL, 20): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, JUL, 21): [
-                0,
-                1,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                1,
-            ],
-            date(2021, JUL, 22): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-            ],
-            date(2021, JUL, 30): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, AUG, 10): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, AUG, 24): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, AUG, 31): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, SEP, 13): [
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, SEP, 16): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, OCT, 2): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-            ],
-            date(2021, OCT, 9): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-            ],
-            date(2021, OCT, 19): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, NOV, 4): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                0,
-                1,
-                1,
-            ],
-            date(2021, NOV, 5): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, NOV, 11): [
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, NOV, 12): [
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, DEC, 3): [
-                0,
-                0,
-                0,
-                1,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-            ],
-            date(2021, DEC, 11): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-            ],
-            date(2021, DEC, 24): [
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-            ],
-            date(2021, DEC, 25): [
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-                1,
-            ],
-            date(2021, DEC, 26): [
-                0,
-                0,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                1,
-            ],
-        }
+        )
+        rows = (
+            (
+                date(2021, JAN, 1),
+                (0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0),
+            ),
+            (
+                date(2021, JAN, 14),
+                (0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, JAN, 28),
+                (1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0),
+            ),
+            (
+                date(2021, FEB, 1),
+                (0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, FEB, 12),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, FEB, 13),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, FEB, 14),
+                (1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1),
+            ),
+            (
+                date(2021, MAR, 4),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1),
+            ),
+            (
+                date(2021, MAR, 11),
+                (0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1),
+            ),
+            (
+                date(2021, MAR, 23),
+                (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, APR, 2),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0),
+            ),
+            (
+                date(2021, APR, 13),
+                (1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, APR, 15),
+                (0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, APR, 26),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1),
+            ),
+            (
+                date(2021, APR, 29),
+                (0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1),
+            ),
+            (
+                date(2021, MAY, 1),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, MAY, 2),
+                (0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1),
+            ),
+            (
+                date(2021, MAY, 13),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, MAY, 14),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, MAY, 16),
+                (1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, MAY, 22),
+                (0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, MAY, 26),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, MAY, 30),
+                (0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0),
+            ),
+            (
+                date(2021, MAY, 31),
+                (0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0),
+            ),
+            (
+                date(2021, JUN, 1),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0),
+            ),
+            (
+                date(2021, JUN, 2),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0),
+            ),
+            (
+                date(2021, JUN, 7),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, JUN, 20),
+                (0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, JUL, 7),
+                (0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, JUL, 10),
+                (0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, JUL, 17),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, JUL, 19),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1),
+            ),
+            (
+                date(2021, JUL, 20),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, JUL, 21),
+                (0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1),
+            ),
+            (
+                date(2021, JUL, 22),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0),
+            ),
+            (
+                date(2021, JUL, 30),
+                (0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, AUG, 10),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, AUG, 24),
+                (0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, AUG, 31),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, SEP, 13),
+                (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, SEP, 16),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, OCT, 2),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0),
+            ),
+            (
+                date(2021, OCT, 9),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0),
+            ),
+            (
+                date(2021, OCT, 19),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, NOV, 4),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1),
+            ),
+            (
+                date(2021, NOV, 5),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, NOV, 11),
+                (0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, NOV, 12),
+                (0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, DEC, 3),
+                (0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0),
+            ),
+            (
+                date(2021, DEC, 11),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0),
+            ),
+            (
+                date(2021, DEC, 24),
+                (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0),
+            ),
+            (
+                date(2021, DEC, 25),
+                (1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1),
+            ),
+            (
+                date(2021, DEC, 26),
+                (0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1),
+            ),
+        )
 
         for col, state in enumerate(columns):
-            my_holidays = holidays.Malaysia(years=2021, subdiv=state)
+            my_holidays = Malaysia(years=2021, subdiv=state)
             # check if all holidays are in here
-            for hol_date, is_holiday in rows.items():
+            for hol_date, is_holiday in rows:
                 if is_holiday[col]:
                     self.assertIn(hol_date, my_holidays)
                 else:
                     self.assertNotIn(hol_date, my_holidays)
 
-    def test_Malaysia(self):
+    def test_malaysia(self):
         # Federal Public Holidays
-
         # https://www.timeanddate.com/holidays/malaysia/2001
-        self.assertIn(date(2001, 1, 24), self.holidays)
-        self.assertIn(date(2001, 1, 25), self.holidays)
-        self.assertIn(date(2001, 3, 6), self.holidays)
-        self.assertIn(date(2001, 3, 26), self.holidays)
-        self.assertIn(date(2001, 5, 1), self.holidays)
-        self.assertIn(date(2001, 5, 7), self.holidays)
-        self.assertIn(date(2001, 6, 2), self.holidays)
-        self.assertIn(date(2001, 6, 4), self.holidays)
-        self.assertIn(date(2001, 8, 31), self.holidays)
-        self.assertIn(date(2001, 11, 14), self.holidays)
-        self.assertIn(date(2001, 12, 17), self.holidays)
-        self.assertIn(date(2001, 12, 18), self.holidays)
-        self.assertIn(date(2001, 12, 25), self.holidays)
+        self.assertHolidayDates(
+            "2001-01-24",
+            "2001-01-25",
+            "2001-03-06",
+            "2001-03-26",
+            "2001-05-01",
+            "2001-05-07",
+            "2001-06-02",
+            "2001-06-04",
+            "2001-08-31",
+            "2001-11-14",
+            "2001-12-17",
+            "2001-12-18",
+            "2001-12-25",
+        )
 
     def test_special_holidays(self):
-        self.assertIn(date(1999, 11, 29), self.holidays)
-        self.assertIn(date(2018, 5, 9), self.holidays)
-        self.assertIn(date(2019, 7, 30), self.holidays)
+        self.assertHoliday(
+            "1999-11-29",
+            "2018-05-09",
+            "2019-07-30",
+        )
+
+    def test_observed(self):
+        dt = (
+            "2012-02-06",
+            "2012-08-21",
+            "2012-09-17",
+            "2013-02-12",
+            "2014-09-01",
+            "2014-10-06",
+            "2015-05-04",
+            "2016-05-02",
+            "2016-12-26",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_JHR_holidays(self):
-        state_holidays = self.johor_holidays
+        state_holidays = self.jhr_holidays
+        self.assertHoliday(
+            state_holidays,
+            # Birthday of the Sultan of Johor
+            "2015-03-23",
+            "2018-03-23",
+            "2020-03-23",
+            "2022-03-23",
+            # Hari Hol of Sultan Iskandar of Johor
+            "2018-10-15",
+            "2019-10-05",
+            "2020-09-24",
+            "2021-09-13",
+            "2022-09-03",
+            "2023-08-22",
+            # Thaipusam
+            "2018-01-31",
+            "2019-01-21",
+            "2020-02-08",
+            "2021-01-28",
+            "2022-01-18",
+            "2023-02-05",
+            # Beginning of Ramadan
+            "2018-05-17",
+            "2019-05-06",
+            "2020-04-24",
+            "2021-04-13",
+            "2022-04-03",
+            "2023-03-23",
+            # Labour Day Holiday
+            "2022-05-04",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Birthday of the Sultan of Johor
+            "2014-03-23",
+            # Hari Hol of Sultan Iskandar of Johor
+            "2010-01-21",
+            # Malaysia Day [In lieu]
+            "2018-09-17",
+        )
+        dt = (
+            "2017-09-03",
+            "2017-12-03",
+            "2018-02-18",
+            "2018-06-17",
+            "2018-09-02",
+            "2020-04-26",
+            "2020-05-03",
+            "2020-08-02",
+            "2020-12-27",
+            "2021-02-14",
+            "2021-05-16",
+            "2022-09-18",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # Birthday of the Sultan of Johor
-        self.assertIn(date(2015, 3, 23), state_holidays)
-        self.assertIn(date(2018, 3, 23), state_holidays)
-        self.assertIn(date(2020, 3, 23), state_holidays)
-        self.assertIn(date(2022, 3, 23), state_holidays)
-        self.assertNotIn(date(2014, 3, 23), state_holidays)
-        # Hari Hol of Sultan Iskandar of Johor
-        self.assertIn(date(2018, 10, 15), state_holidays)
-        self.assertIn(date(2019, 10, 5), state_holidays)
-        self.assertIn(date(2020, 9, 24), state_holidays)
-        self.assertIn(date(2021, 9, 13), state_holidays)
-        self.assertIn(date(2022, 9, 3), state_holidays)
-        self.assertIn(date(2023, 8, 22), state_holidays)
-        self.assertNotIn(date(2010, 1, 21), state_holidays)
-        # Thaipusam
-        self.assertIn(date(2018, 1, 31), state_holidays)
-        self.assertIn(date(2019, 1, 21), state_holidays)
-        self.assertIn(date(2020, 2, 8), state_holidays)
-        self.assertIn(date(2021, 1, 28), state_holidays)
-        self.assertIn(date(2022, 1, 18), state_holidays)
-        self.assertIn(date(2023, 2, 5), state_holidays)
-        # Beginning of Ramadan
-        self.assertIn(date(2018, 5, 17), state_holidays)
-        self.assertIn(date(2019, 5, 6), state_holidays)
-        self.assertIn(date(2020, 4, 24), state_holidays)
-        self.assertIn(date(2020, 4, 26), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 13), state_holidays)
-        self.assertIn(date(2022, 4, 3), state_holidays)
-        self.assertIn(date(2023, 3, 23), state_holidays)
-        # Labour Day Holiday
-        self.assertIn(date(2022, 5, 4), state_holidays)
-        # Malaysia Day [In lieu]
-        self.assertNotIn(date(2018, 9, 17), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_KDH_holidays(self):
-        state_holidays = self.kedah_holidays
+        state_holidays = self.kdh_holidays
+        self.assertHoliday(
+            state_holidays,
+            # Hari Raya Haji
+            "2006-12-31",
+            "2018-08-22",
+            "2019-08-11",
+            "2020-07-31",
+            "2021-07-20",
+            "2022-07-10",
+            "2023-06-28",
+            # Hari Raya Haji Holiday
+            "2007-01-01",
+            "2018-08-23",
+            "2019-08-12",
+            "2020-08-01",
+            "2021-07-21",
+            "2022-07-11",
+            "2023-06-29",
+            # Isra and Mi'raj
+            "2018-04-14",
+            "2019-04-03",
+            "2020-03-22",
+            "2021-03-11",
+            "2022-03-01",
+            "2023-02-18",
+            # Beginning of Ramadan
+            "2018-05-17",
+            "2019-05-06",
+            "2020-04-24",
+            "2021-04-13",
+            "2022-04-03",
+            "2023-03-23",
+            # Thaipusam in 2022
+            "2022-01-18",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Malaysia Day [In lieu]
+            "2018-09-17",
+        )
+        dt = (
+            "2017-09-03",
+            "2017-12-03",
+            "2018-02-18",
+            "2018-06-17",
+            "2018-09-02",
+            "2020-04-26",
+            "2020-05-03",
+            "2020-08-02",
+            "2020-12-27",
+            "2021-02-14",
+            "2021-05-16",
+            "2022-09-18",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # Hari Raya Haji
-        self.assertIn(date(2006, 12, 31), state_holidays)
-        self.assertIn(date(2018, 8, 22), state_holidays)
-        self.assertIn(date(2019, 8, 11), state_holidays)
-        self.assertIn(date(2020, 7, 31), state_holidays)
-        self.assertIn(date(2021, 7, 20), state_holidays)
-        self.assertIn(date(2022, 7, 10), state_holidays)
-        self.assertIn(date(2023, 6, 28), state_holidays)
-        # Hari Raya Haji Holiday
-        self.assertIn(date(2007, 1, 1), state_holidays)
-        self.assertIn(date(2018, 8, 23), state_holidays)
-        self.assertIn(date(2019, 8, 12), state_holidays)
-        self.assertIn(date(2020, 8, 1), state_holidays)
-        self.assertIn(date(2020, 8, 2), state_holidays)  # In lieu
-        self.assertIn(date(2021, 7, 21), state_holidays)
-        self.assertIn(date(2022, 7, 11), state_holidays)
-        self.assertIn(date(2023, 6, 29), state_holidays)
-        # Isra and Mi'raj
-        self.assertIn(date(2018, 4, 14), state_holidays)
-        self.assertIn(date(2019, 4, 3), state_holidays)
-        self.assertIn(date(2020, 3, 22), state_holidays)
-        self.assertIn(date(2021, 3, 11), state_holidays)
-        self.assertIn(date(2022, 3, 1), state_holidays)
-        self.assertIn(date(2023, 2, 18), state_holidays)
-        # Beginning of Ramadan
-        self.assertIn(date(2018, 5, 17), state_holidays)
-        self.assertIn(date(2019, 5, 6), state_holidays)
-        self.assertIn(date(2020, 4, 24), state_holidays)
-        self.assertIn(date(2020, 4, 26), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 13), state_holidays)
-        self.assertIn(date(2022, 4, 3), state_holidays)
-        self.assertIn(date(2023, 3, 23), state_holidays)
-        # Thaipusam in 2022
-        self.assertIn(date(2022, 1, 18), state_holidays)
-        # Malaysia Day [In lieu]
-        self.assertNotIn(date(2018, 9, 17), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_KTN_holidays(self):
-        state_holidays = self.kelantan_holidays
+        state_holidays = self.ktn_holidays
+        self.assertHoliday(
+            state_holidays,
+            # Birthday of the Sultan of Kelantan
+            "2018-11-11",
+            "2019-11-12",
+            "2020-11-11",
+            # Hari Raya Haji
+            "2006-12-31",
+            "2018-08-22",
+            "2019-08-11",
+            "2020-07-31",
+            "2021-07-20",
+            "2022-07-10",
+            "2023-06-28",
+            # Hari Raya Haji Holiday
+            "2007-01-01",
+            "2018-08-23",
+            "2019-08-12",
+            "2020-08-01",
+            "2021-07-21",
+            "2022-07-11",
+            "2023-06-29",
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            "2023-04-09",  # In lieu
+            # Labour Day Holiday
+            "2022-05-04",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Birthday of the Sultan of Kelantan
+            "2001-11-11",
+            # Malaysia Day [In lieu]
+            "2018-09-17",
+        )
+        dt = (
+            "2017-01-30",
+            "2017-06-04",
+            "2017-09-03",
+            "2017-09-17",
+            "2018-02-18",
+            "2018-06-03",
+            "2018-06-17",
+            "2019-11-10",
+            "2020-01-27",
+            "2020-08-02",
+            "2020-11-15",
+            "2021-02-14",
+            "2021-05-02",
+            "2021-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # Birthday of the Sultan of Kelantan
-        self.assertIn(date(2018, 11, 11), state_holidays)
-        self.assertIn(date(2019, 11, 12), state_holidays)
-        self.assertIn(date(2020, 11, 11), state_holidays)
-        self.assertNotIn(date(2001, 11, 11), state_holidays)
-        # Hari Raya Haji
-        self.assertIn(date(2006, 12, 31), state_holidays)
-        self.assertIn(date(2018, 8, 22), state_holidays)
-        self.assertIn(date(2019, 8, 11), state_holidays)
-        self.assertIn(date(2020, 7, 31), state_holidays)
-        self.assertIn(date(2021, 7, 20), state_holidays)
-        self.assertIn(date(2022, 7, 10), state_holidays)
-        self.assertIn(date(2023, 6, 28), state_holidays)
-        # Hari Raya Haji Holiday
-        self.assertIn(date(2007, 1, 1), state_holidays)
-        self.assertIn(date(2018, 8, 23), state_holidays)
-        self.assertIn(date(2019, 8, 12), state_holidays)
-        self.assertIn(date(2020, 8, 1), state_holidays)
-        self.assertIn(date(2020, 8, 2), state_holidays)  # In lieu
-        self.assertIn(date(2021, 7, 21), state_holidays)
-        self.assertIn(date(2022, 7, 11), state_holidays)
-        self.assertIn(date(2023, 6, 29), state_holidays)
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2018, 6, 3), state_holidays)  # In lieu
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        self.assertIn(date(2023, 4, 9), state_holidays)  # In lieu
-        # Labour Day Holiday
-        self.assertIn(date(2022, 5, 4), state_holidays)
-        # Malaysia Day [In lieu]
-        self.assertNotIn(date(2018, 9, 17), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_NSN_holidays(self):
-        state_holidays = self.negeri_sembilan_holidays
+        state_holidays = self.nsn_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Isra and Mi'raj
+            "2018-04-14",
+            "2019-04-03",
+            "2020-03-22",
+            "2021-03-11",
+            "2022-03-01",
+            "2023-02-18",
+            # Birthday of the Sultan of Negeri Sembilan
+            "2018-01-14",
+            "2023-01-14",
+            # Thaipusam
+            "2018-01-31",
+            "2019-01-21",
+            "2020-02-08",
+            "2021-01-28",
+            "2022-01-18",
+            "2023-02-05",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Birthday of the Sultan of Negeri Sembilan
+            "2008-01-14",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-01-15",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-03-23",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Isra and Mi'raj
-        self.assertIn(date(2018, 4, 14), state_holidays)
-        self.assertIn(date(2019, 4, 3), state_holidays)
-        self.assertIn(date(2020, 3, 22), state_holidays)
-        self.assertIn(date(2021, 3, 11), state_holidays)
-        self.assertIn(date(2022, 3, 1), state_holidays)
-        self.assertIn(date(2023, 2, 18), state_holidays)
-        # Birthday of the Sultan of Negeri Sembilan
-        self.assertIn(date(2018, 1, 14), state_holidays)
-        self.assertIn(date(2023, 1, 14), state_holidays)
-        self.assertNotIn(date(2008, 1, 14), state_holidays)
-        # Thaipusam
-        self.assertIn(date(2018, 1, 31), state_holidays)
-        self.assertIn(date(2019, 1, 21), state_holidays)
-        self.assertIn(date(2020, 2, 8), state_holidays)
-        self.assertIn(date(2021, 1, 28), state_holidays)
-        self.assertIn(date(2022, 1, 18), state_holidays)
-        self.assertIn(date(2023, 2, 5), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_PNG_holidays(self):
-        state_holidays = self.penang_holidays
+        state_holidays = self.png_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            # Thaipusam
+            "2018-01-31",
+            "2019-01-21",
+            "2020-02-08",
+            "2021-01-28",
+            "2022-01-18",
+            "2023-02-05",
+            "2023-02-06",  # In lieu
+            # George Town Heritage Day
+            "2009-07-07",
+            "2020-07-07",
+            # Birthday of the Governor of Penang
+            "2017-07-08",
+            "2019-07-13",
+            "2020-07-11",
+            "2022-07-09",
+            "2023-07-08",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # George Town Heritage Day
+            "2008-07-07",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-07-08",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-11",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2020, 5, 11), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        # Thaipusam
-        self.assertIn(date(2018, 1, 31), state_holidays)
-        self.assertIn(date(2019, 1, 21), state_holidays)
-        self.assertIn(date(2020, 2, 8), state_holidays)
-        self.assertIn(date(2021, 1, 28), state_holidays)
-        self.assertIn(date(2022, 1, 18), state_holidays)
-        self.assertIn(date(2023, 2, 5), state_holidays)
-        self.assertIn(date(2023, 2, 6), state_holidays)  # In lieu
-        # George Town Heritage Day
-        self.assertIn(date(2009, 7, 7), state_holidays)
-        self.assertIn(date(2020, 7, 7), state_holidays)
-        self.assertNotIn(date(2008, 7, 7), state_holidays)
-        # Birthday of the Governor of Penang
-        self.assertIn(date(2017, 7, 8), state_holidays)
-        self.assertIn(date(2019, 7, 13), state_holidays)
-        self.assertIn(date(2020, 7, 11), state_holidays)
-        self.assertIn(date(2022, 7, 9), state_holidays)
-        self.assertIn(date(2023, 7, 8), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_PRK_holidays(self):
-        state_holidays = self.perak_holidays
+        state_holidays = self.prk_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            # Thaipusam
+            "2018-01-31",
+            "2019-01-21",
+            "2020-02-08",
+            "2021-01-28",
+            "2022-01-18",
+            "2023-02-05",
+            "2023-02-06",  # In lieu
+            # Birthday of the Sultan of Perak
+            "2009-11-27",
+            "2017-11-27",
+            "2018-11-02",
+            "2019-11-01",
+            "2020-11-06",
+            "2021-11-05",
+            "2022-11-04",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Birthday of the Sultan of Perak
+            "2018-11-27",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-11",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2020, 5, 11), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        # Thaipusam
-        self.assertIn(date(2018, 1, 31), state_holidays)
-        self.assertIn(date(2019, 1, 21), state_holidays)
-        self.assertIn(date(2020, 2, 8), state_holidays)
-        self.assertIn(date(2021, 1, 28), state_holidays)
-        self.assertIn(date(2022, 1, 18), state_holidays)
-        self.assertIn(date(2023, 2, 5), state_holidays)
-        self.assertIn(date(2023, 2, 6), state_holidays)  # In lieu
-        # Birthday of the Sultan of Perak
-        self.assertIn(date(2009, 11, 27), state_holidays)
-        self.assertIn(date(2017, 11, 27), state_holidays)
-        self.assertIn(date(2018, 11, 2), state_holidays)
-        self.assertIn(date(2019, 11, 1), state_holidays)
-        self.assertIn(date(2020, 11, 6), state_holidays)
-        self.assertIn(date(2021, 11, 5), state_holidays)
-        self.assertIn(date(2022, 11, 4), state_holidays)
-        self.assertNotIn(date(2018, 11, 27), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_SBH_holidays(self):
-        state_holidays = self.sabah_holidays
+        state_holidays = self.sbh_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Pesta Kaamatan
+            "2018-05-30",
+            "2019-05-31",
+            # Good Friday
+            "2018-03-30",
+            "2020-04-10",
+            "2021-04-02",
+            "2022-04-15",
+            "2023-04-07",
+            # Birthday of the Governor of Sabah
+            "2017-10-07",
+            "2018-10-06",
+            "2019-10-05",
+            "2020-10-03",
+            # Christmas Eve
+            "2019-12-24",
+            "2020-12-24",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Christmas Eve
+            "2018-12-24",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Pesta Kaamatan
-        self.assertIn(date(2018, 5, 30), state_holidays)
-        self.assertIn(date(2019, 5, 31), state_holidays)
-        # Good Friday
-        self.assertIn(date(2018, 3, 30), state_holidays)
-        self.assertIn(date(2020, 4, 10), state_holidays)
-        self.assertIn(date(2021, 4, 2), state_holidays)
-        self.assertIn(date(2022, 4, 15), state_holidays)
-        self.assertIn(date(2023, 4, 7), state_holidays)
-        # Birthday of the Governor of Sabah
-        self.assertIn(date(2017, 10, 7), state_holidays)
-        self.assertIn(date(2018, 10, 6), state_holidays)
-        self.assertIn(date(2019, 10, 5), state_holidays)
-        self.assertIn(date(2020, 10, 3), state_holidays)
-        # Christmas Eve
-        self.assertIn(date(2019, 12, 24), state_holidays)
-        self.assertIn(date(2020, 12, 24), state_holidays)
-        self.assertNotIn(date(2018, 12, 24), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_SWK_holidays(self):
-        state_holidays = self.sarawak_holidays
+        state_holidays = self.swk_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Good Friday
+            "2018-03-30",
+            "2020-04-10",
+            "2021-04-02",
+            "2022-04-15",
+            "2023-04-07",
+            # Gawai Dayak
+            "2018-06-01",
+            "2018-06-02",
+            "2020-06-02",
+            "2020-06-02",
+            # Birthday of the Governor of Sarawak
+            "2018-10-13",
+            "2019-10-12",
+            "2020-10-10",
+            "2021-10-09",
+            "2022-10-08",
+            # Sarawak Day
+            "2017-07-22",
+            "2018-07-22",
+            "2022-07-22",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Sarawak Day
+            "2014-07-22",
+            # Deepavali
+            "2018-11-06",
+            "2022-10-24",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-07-23",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-06-04",
+            "2019-08-12",
+            "2020-01-27",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Good Friday
-        self.assertIn(date(2018, 3, 30), state_holidays)
-        self.assertIn(date(2020, 4, 10), state_holidays)
-        self.assertIn(date(2021, 4, 2), state_holidays)
-        self.assertIn(date(2022, 4, 15), state_holidays)
-        self.assertIn(date(2023, 4, 7), state_holidays)
-        # Gawai Dayak
-        self.assertIn(date(2018, 6, 1), state_holidays)
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2020, 6, 2), state_holidays)
-        self.assertIn(date(2020, 6, 2), state_holidays)
-        # Birthday of the Governor of Sarawak
-        self.assertIn(date(2018, 10, 13), state_holidays)
-        self.assertIn(date(2019, 10, 12), state_holidays)
-        self.assertIn(date(2020, 10, 10), state_holidays)
-        self.assertIn(date(2021, 10, 9), state_holidays)
-        self.assertIn(date(2022, 10, 8), state_holidays)
-        # Sarawak Day
-        self.assertIn(date(2017, 7, 22), state_holidays)
-        self.assertIn(date(2018, 7, 22), state_holidays)
-        self.assertIn(date(2018, 7, 23), state_holidays)  # In lieu
-        self.assertIn(date(2022, 7, 22), state_holidays)
-        self.assertNotIn(date(2014, 7, 22), state_holidays)
-        # Deepavali
-        self.assertNotIn(date(2018, 11, 6), state_holidays)
-        self.assertNotIn(date(2022, 10, 24), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_SGR_holidays(self):
-        state_holidays = self.selangor_holidays
+        state_holidays = self.sgr_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            # Thaipusam
+            "2018-01-31",
+            "2019-01-21",
+            "2020-02-08",
+            "2021-01-28",
+            "2022-01-18",
+            "2023-02-05",
+            "2023-02-06",  # In lieu
+            # Birthday of The Sultan of Selangor
+            "2018-12-11",
+            "2019-12-11",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-11",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-12",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2020, 5, 11), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        # Thaipusam
-        self.assertIn(date(2018, 1, 31), state_holidays)
-        self.assertIn(date(2019, 1, 21), state_holidays)
-        self.assertIn(date(2020, 2, 8), state_holidays)
-        self.assertIn(date(2021, 1, 28), state_holidays)
-        self.assertIn(date(2022, 1, 18), state_holidays)
-        self.assertIn(date(2023, 2, 5), state_holidays)
-        self.assertIn(date(2023, 2, 6), state_holidays)  # In lieu
-        # Birthday of The Sultan of Selangor
-        self.assertIn(date(2018, 12, 11), state_holidays)
-        self.assertIn(date(2019, 12, 11), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_TRG_holidays(self):
-        state_holidays = self.terengganu_holidays
+        state_holidays = self.trg_holidays
+        self.assertHoliday(
+            state_holidays,
+            # Arafat Day
+            "2018-08-21",
+            "2019-08-10",
+            "2020-07-30",
+            "2021-07-19",
+            "2022-07-09",
+            "2023-06-27",
+            # Hari Raya Haji
+            "2006-12-31",
+            "2018-08-22",
+            "2019-08-11",
+            "2020-07-31",
+            "2021-07-20",
+            "2022-07-10",
+            "2023-06-28",
+            # Hari Raya Haji Holiday
+            "2007-01-01",
+            "2018-08-23",
+            "2019-08-12",
+            "2020-08-01",
+            "2021-07-21",
+            "2022-07-11",
+            "2023-06-29",
+            # Isra and Mi'raj
+            "2020-03-22",
+            "2021-03-11",
+            "2022-03-01",
+            "2023-02-18",
+            "2023-02-19",  # In lieu
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            "2023-04-09",  # In lieu
+            # Anniversary of the Installation of the Sultan of Terengganu
+            "2000-03-04",
+            "2018-03-04",
+            "2019-03-04",
+            # Birthday of the Sultan of Terengganu
+            "2020-04-26",
+            "2022-04-26",
+            # Labour Day Holiday
+            "2022-05-04",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Isra and Mi'raj
+            "2018-04-14",
+            "2019-04-03",
+            # Anniversary of the Installation of the Sultan of Terengganu
+            "1999-03-04",
+            # Birthday of the Sultan of Terengganu
+            "1999-04-26",
+            # Malaysia Day [In lieu]
+            "2018-09-17",
+        )
+        dt = (
+            "2017-01-30",
+            "2017-03-05",
+            "2017-06-04",
+            "2017-09-03",
+            "2017-09-17",
+            "2018-02-18",
+            "2018-06-03",
+            "2018-06-17",
+            "2019-08-13",
+            "2019-11-10",
+            "2020-01-27",
+            "2020-08-02",
+            "2020-11-15",
+            "2021-02-14",
+            "2021-05-02",
+            "2021-12-26",
+            "2022-07-12",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # Arafat Day
-        self.assertIn(date(2018, 8, 21), state_holidays)
-        self.assertIn(date(2019, 8, 10), state_holidays)
-        self.assertIn(date(2019, 8, 13), state_holidays)  # In lieu
-        self.assertIn(date(2020, 7, 30), state_holidays)
-        self.assertIn(date(2021, 7, 19), state_holidays)
-        self.assertIn(date(2022, 7, 9), state_holidays)
-        self.assertIn(date(2022, 7, 12), state_holidays)  # In lieu
-        self.assertIn(date(2023, 6, 27), state_holidays)
-        # Hari Raya Haji
-        self.assertIn(date(2006, 12, 31), state_holidays)
-        self.assertIn(date(2018, 8, 22), state_holidays)
-        self.assertIn(date(2019, 8, 11), state_holidays)
-        self.assertIn(date(2020, 7, 31), state_holidays)
-        self.assertIn(date(2021, 7, 20), state_holidays)
-        self.assertIn(date(2022, 7, 10), state_holidays)
-        self.assertIn(date(2023, 6, 28), state_holidays)
-        # Hari Raya Haji Holiday
-        self.assertIn(date(2007, 1, 1), state_holidays)
-        self.assertIn(date(2018, 8, 23), state_holidays)
-        self.assertIn(date(2019, 8, 12), state_holidays)
-        self.assertIn(date(2020, 8, 1), state_holidays)
-        self.assertIn(date(2020, 8, 2), state_holidays)  # In lieu
-        self.assertIn(date(2021, 7, 21), state_holidays)
-        self.assertIn(date(2022, 7, 11), state_holidays)
-        self.assertIn(date(2023, 6, 29), state_holidays)
-        # Isra and Mi'raj
-        self.assertIn(date(2020, 3, 22), state_holidays)
-        self.assertIn(date(2021, 3, 11), state_holidays)
-        self.assertIn(date(2022, 3, 1), state_holidays)
-        self.assertIn(date(2023, 2, 18), state_holidays)
-        self.assertIn(date(2023, 2, 19), state_holidays)  # In lieu
-        self.assertNotIn(date(2018, 4, 14), state_holidays)
-        self.assertNotIn(date(2019, 4, 3), state_holidays)
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2018, 6, 3), state_holidays)  # In lieu
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        self.assertIn(date(2023, 4, 9), state_holidays)  # In lieu
-        # Anniversary of the Installation of the Sultan of Terengganu
-        self.assertIn(date(2000, 3, 4), state_holidays)
-        self.assertIn(date(2018, 3, 4), state_holidays)
-        self.assertIn(date(2019, 3, 4), state_holidays)
-        self.assertNotIn(date(1999, 3, 4), state_holidays)
-        # Birthday of the Sultan of Terengganu
-        self.assertIn(date(2020, 4, 26), state_holidays)
-        self.assertIn(date(2022, 4, 26), state_holidays)
-        self.assertNotIn(date(1999, 4, 26), state_holidays)
-        # Labour Day Holiday
-        self.assertIn(date(2022, 5, 4), state_holidays)
-        # Malaysia Day [In lieu]
-        self.assertNotIn(date(2018, 9, 17), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_KUL_holidays(self):
-        state_holidays = self.kuala_lumpur_holidays
+        state_holidays = self.kul_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Federal Territory Day
+            "2018-02-01",
+            "2019-02-01",
+            # Thaipusam
+            "2018-01-31",
+            "2019-01-21",
+            "2020-02-08",
+            "2021-01-28",
+            "2022-01-18",
+            "2023-02-05",
+            # Malaysia Cup Holiday
+            "2021-12-03",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Federal Territory Day
+            "1970-02-01",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-11",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Federal Territory Day
-        self.assertIn(date(2018, 2, 1), state_holidays)
-        self.assertIn(date(2019, 2, 1), state_holidays)
-        self.assertNotIn(date(1970, 2, 1), state_holidays)
-        # Thaipusam
-        self.assertIn(date(2018, 1, 31), state_holidays)
-        self.assertIn(date(2019, 1, 21), state_holidays)
-        self.assertIn(date(2020, 2, 8), state_holidays)
-        self.assertIn(date(2021, 1, 28), state_holidays)
-        self.assertIn(date(2022, 1, 18), state_holidays)
-        self.assertIn(date(2023, 2, 5), state_holidays)
-        # Malaysia Cup Holiday
-        self.assertIn(date(2021, 12, 3), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_MLK_holidays(self):
-        state_holidays = self.malacca_holidays
+        state_holidays = self.mlk_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Beginning of Ramadan
+            "2018-05-17",
+            "2019-05-06",
+            "2020-04-24",
+            "2021-04-13",
+            "2022-04-03",
+            "2023-03-23",
+            # Declaration of Malacca as a Historical City
+            "2018-04-15",
+            "2019-04-15",
+            # Birthday of the Governor of Malacca
+            "2018-10-12",
+            "2019-10-11",
+            "2020-08-24",
+            "2021-08-24",
+            "2022-08-24",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Declaration of Malacca as a Historical City
+            "1985-04-15",
+            # Birthday of the Governor of Malacca
+            "2019-08-24",
+            "2020-10-09",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-04-16",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-26",
+            "2022-04-04",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Beginning of Ramadan
-        self.assertIn(date(2018, 5, 17), state_holidays)
-        self.assertIn(date(2019, 5, 6), state_holidays)
-        self.assertIn(date(2020, 4, 24), state_holidays)
-        self.assertIn(date(2021, 4, 13), state_holidays)
-        self.assertIn(date(2022, 4, 3), state_holidays)
-        self.assertIn(date(2022, 4, 4), state_holidays)  # In lieu
-        self.assertIn(date(2023, 3, 23), state_holidays)
-        # Declaration of Malacca as a Historical City
-        self.assertIn(date(2018, 4, 15), state_holidays)
-        self.assertIn(date(2019, 4, 15), state_holidays)
-        self.assertNotIn(date(1985, 4, 15), state_holidays)
-        # Birthday of the Governor of Malacca
-        self.assertIn(date(2018, 10, 12), state_holidays)
-        self.assertIn(date(2019, 10, 11), state_holidays)
-        self.assertIn(date(2020, 8, 24), state_holidays)
-        self.assertIn(date(2021, 8, 24), state_holidays)
-        self.assertIn(date(2022, 8, 24), state_holidays)
-        self.assertNotIn(date(2019, 8, 24), state_holidays)
-        self.assertNotIn(date(2020, 10, 9), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_LBN_holidays(self):
-        state_holidays = self.labuan_holidays
+        state_holidays = self.lbn_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Federal Territory Day
+            "2020-02-01",
+            "2022-02-01",
+            # Pesta Kaamatan
+            "2018-05-30",
+            "2019-05-31",
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            # Malaysia Cup Holiday
+            "2021-12-03",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Federal Territory Day
+            "1970-02-01",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-11",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Federal Territory Day
-        self.assertIn(date(2020, 2, 1), state_holidays)
-        self.assertIn(date(2022, 2, 1), state_holidays)
-        self.assertNotIn(date(1970, 2, 1), state_holidays)
-        # Pesta Kaamatan
-        self.assertIn(date(2018, 5, 30), state_holidays)
-        self.assertIn(date(2019, 5, 31), state_holidays)
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2020, 5, 11), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        # Malaysia Cup Holiday
-        self.assertIn(date(2021, 12, 3), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_PHG_holidays(self):
-        state_holidays = self.pahang_holidays
-
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2020, 5, 11), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        # Hari Hol of Pahang
-        self.assertIn(date(2001, 5, 7), state_holidays)
-        self.assertIn(date(2018, 5, 7), state_holidays)
-        self.assertIn(date(2019, 5, 7), state_holidays)
-        self.assertIn(date(2020, 5, 22), state_holidays)
-        self.assertIn(date(2021, 5, 22), state_holidays)
-        self.assertIn(date(2022, 5, 22), state_holidays)
-        self.assertNotIn(date(2010, 5, 22), state_holidays)
-        self.assertNotIn(date(2021, 5, 7), state_holidays)
-        self.assertNotEqual(
-            state_holidays[date(2020, 5, 7)], "Hari Hol of Pahang"
+        state_holidays = self.phg_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            # Hari Hol of Pahang
+            "2001-05-07",
+            "2018-05-07",
+            "2019-05-07",
+            "2020-05-07",
+            "2021-05-22",
+            "2022-05-22",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Hari Hol of Pahang
+            "2010-05-22",
+            "2021-05-07",
         )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-05-08",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-11",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-05-23",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
+
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_PLS_holidays(self):
-        state_holidays = self.perlis_holidays
+        state_holidays = self.pls_holidays
+        self.assertHoliday(
+            state_holidays,
+            # Hari Raya Haji
+            "2006-12-31",
+            "2018-08-22",
+            "2019-08-11",
+            "2020-07-31",
+            "2021-07-20",
+            "2022-07-10",
+            "2023-06-28",
+            # Hari Raya Haji Holiday
+            "2007-01-01",
+            "2018-08-23",
+            "2019-08-12",
+            "2020-08-01",
+            "2021-07-21",
+            "2022-07-11",
+            "2023-06-29",
+            # Isra and Mi'raj
+            "2018-04-14",
+            "2019-04-03",
+            "2020-03-22",
+            "2021-03-11",
+            "2022-03-01",
+            "2023-02-18",
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            # Birthday of The Raja of Perlis
+            "2000-05-17",
+            "2010-05-17",
+            "2017-05-17",
+            "2018-07-17",
+            "2022-07-17",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Birthday of The Raja of Perlis
+            "2017-07-17",
+            "2018-05-17",
+        )
+        dt = (
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-13",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-03-23",
+            "2020-05-11",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-12",
+            "2022-07-18",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-        # Hari Raya Haji
-        self.assertIn(date(2006, 12, 31), state_holidays)
-        self.assertIn(date(2018, 8, 22), state_holidays)
-        self.assertIn(date(2019, 8, 11), state_holidays)
-        self.assertIn(date(2020, 7, 31), state_holidays)
-        self.assertIn(date(2021, 7, 20), state_holidays)
-        self.assertIn(date(2022, 7, 10), state_holidays)
-        self.assertIn(date(2023, 6, 28), state_holidays)
-        # Hari Raya Haji Holiday
-        self.assertIn(date(2007, 1, 1), state_holidays)
-        self.assertIn(date(2018, 8, 23), state_holidays)
-        self.assertIn(date(2019, 8, 12), state_holidays)
-        self.assertIn(date(2019, 8, 13), state_holidays)  # In lieu
-        self.assertIn(date(2020, 8, 1), state_holidays)
-        self.assertIn(date(2021, 7, 21), state_holidays)
-        self.assertIn(date(2022, 7, 11), state_holidays)
-        self.assertIn(date(2022, 7, 12), state_holidays)  # In lieu
-        self.assertIn(date(2023, 6, 29), state_holidays)
-        # Isra and Mi'raj
-        self.assertIn(date(2018, 4, 14), state_holidays)
-        self.assertIn(date(2019, 4, 3), state_holidays)
-        self.assertIn(date(2020, 3, 22), state_holidays)
-        self.assertIn(date(2020, 3, 23), state_holidays)  # In lieu
-        self.assertIn(date(2021, 3, 11), state_holidays)
-        self.assertIn(date(2022, 3, 1), state_holidays)
-        self.assertIn(date(2023, 2, 18), state_holidays)
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2020, 5, 11), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        # Birthday of The Raja of Perlis
-        self.assertIn(date(2000, 5, 17), state_holidays)
-        self.assertIn(date(2010, 5, 17), state_holidays)
-        self.assertIn(date(2017, 5, 17), state_holidays)
-        self.assertIn(date(2018, 7, 17), state_holidays)
-        self.assertIn(date(2022, 7, 17), state_holidays)
-        self.assertNotIn(date(2017, 7, 17), state_holidays)
-        self.assertNotIn(date(2018, 5, 17), state_holidays)
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
 
     def test_PJY_holidays(self):
-        state_holidays = self.putrajaya_holidays
-
-        # New Year's Day
-        self.assertIn(date(2018, 1, 1), state_holidays)
-        self.assertIn(date(2020, 1, 1), state_holidays)
-        self.assertIn(date(2022, 1, 1), state_holidays)
-        self.assertIn(date(2023, 1, 2), state_holidays)  # In lieu
-        # Nuzul Al-Quran Day
-        self.assertIn(date(2018, 6, 2), state_holidays)
-        self.assertIn(date(2019, 5, 22), state_holidays)
-        self.assertIn(date(2020, 5, 10), state_holidays)
-        self.assertIn(date(2020, 5, 11), state_holidays)  # In lieu
-        self.assertIn(date(2021, 4, 29), state_holidays)
-        self.assertIn(date(2022, 4, 19), state_holidays)
-        self.assertIn(date(2023, 4, 8), state_holidays)
-        # Thaipusam
-        self.assertIn(date(2018, 1, 31), state_holidays)
-        self.assertIn(date(2019, 1, 21), state_holidays)
-        self.assertIn(date(2020, 2, 8), state_holidays)
-        self.assertIn(date(2021, 1, 28), state_holidays)
-        self.assertIn(date(2022, 1, 18), state_holidays)
-        self.assertIn(date(2023, 2, 5), state_holidays)
-        self.assertIn(date(2023, 2, 6), state_holidays)  # In lieu
-        # Federal Territory Day
-        self.assertIn(date(2018, 2, 1), state_holidays)
-        self.assertIn(date(2019, 2, 1), state_holidays)
-        self.assertNotIn(date(1970, 2, 1), state_holidays)
-        # Malaysia Cup Holiday
-        self.assertIn(date(2021, 12, 3), state_holidays)
+        state_holidays = self.pjy_holidays
+        self.assertHoliday(
+            state_holidays,
+            # New Year's Day
+            "2018-01-01",
+            "2020-01-01",
+            "2022-01-01",
+            "2023-01-02",  # In lieu
+            # Nuzul Al-Quran Day
+            "2018-06-02",
+            "2019-05-22",
+            "2020-05-10",
+            "2021-04-29",
+            "2022-04-19",
+            "2023-04-08",
+            # Thaipusam
+            "2018-01-31",
+            "2019-01-21",
+            "2020-02-08",
+            "2021-01-28",
+            "2022-01-18",
+            "2023-02-05",
+            "2023-02-06",  # In lieu
+            # Federal Territory Day
+            "2018-02-01",
+            "2019-02-01",
+            # Malaysia Cup Holiday
+            "2021-12-03",
+        )
+        self.assertNoHoliday(
+            state_holidays,
+            # Federal Territory Day
+            "1970-02-01",
+        )
+        dt = (
+            "2017-01-02",
+            "2017-01-30",
+            "2017-06-27",
+            "2018-09-10",
+            "2018-09-17",
+            "2019-05-20",
+            "2019-08-12",
+            "2019-10-28",
+            "2020-01-27",
+            "2020-05-11",
+            "2020-05-26",
+            "2022-05-04",
+            "2022-05-16",
+            "2022-07-11",
+            "2022-12-26",
+        )
+        self.assertHoliday(state_holidays, dt)
 
-    def test_aliases(self):
-        holidays1 = holidays.MY()
-        holidays2 = holidays.MYS()
-        self.assertEqual(list(holidays1), list(holidays2))
+        state_holidays.observed = False
+        self.assertNoNonObservedHoliday(state_holidays, dt)
diff --git a/tests/countries/test_mexico.py b/tests/countries/test_mexico.py
index d7587a49c..2881a3311 100644
--- a/tests/countries/test_mexico.py
+++ b/tests/countries/test_mexico.py
@@ -9,199 +9,148 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import unittest
-from datetime import date
-from datetime import timedelta as td
+from holidays.countries.mexico import Mexico, MX, MEX
+from tests.common import TestCase
 
-import holidays
 
-
-class TestMX(unittest.TestCase):
+class TestMX(TestCase):
     def setUp(self):
-        self.holidays = holidays.MX(observed=False)
+        self.holidays = Mexico()
+
+    def test_country_aliases(self):
+        self.assertCountryAliases(Mexico, MX, MEX)
 
-    def test_new_years(self):
-        self.assertNotIn(date(2010, 12, 31), self.holidays)
-        self.assertNotIn(date(2017, 1, 2), self.holidays)
-        self.holidays.observed = True
-        self.assertIn(date(2010, 12, 31), self.holidays)
-        self.assertIn(date(2017, 1, 2), self.holidays)
-        self.holidays.observed = False
-        for year in range(1900, 2100):
-            dt = date(year, 1, 1)
-            self.assertIn(dt, self.holidays)
-            self.assertNotIn(dt + td(days=-1), self.holidays)
-            self.assertNotIn(dt + td(days=+1), self.holidays)
+    def test_new_years_day(self):
+        self.assertHoliday(f"{year}-01-01" for year in range(1900, 2100))
 
     def test_constitution_day(self):
-        for dt in [
-            date(2005, 2, 5),
-            date(2006, 2, 5),
-            date(2007, 2, 5),
-            date(2009, 2, 5),
-            date(2010, 2, 5),
-            date(2015, 2, 5),
-            date(2016, 2, 5),
-            date(2020, 2, 5),
-            date(2021, 2, 5),
-            date(2022, 2, 5),
-        ]:
-            self.assertIn(dt, self.holidays)
-            self.assertNotIn(dt + td(days=-1), self.holidays)
-            self.assertNotIn(dt + td(days=+1), self.holidays)
-        self.holidays.observed = True
-        for dt in [
-            date(2005, 2, 5),
-            date(2006, 2, 5),
-            date(2007, 2, 5),
-            date(2009, 2, 5),
-            date(2009, 2, 2),
-            date(2010, 2, 5),
-            date(2010, 2, 1),
-            date(2015, 2, 5),
-            date(2015, 2, 2),
-            date(2016, 2, 5),
-            date(2016, 2, 1),
-            date(2020, 2, 5),
-            date(2020, 2, 3),
-            date(2021, 2, 5),
-            date(2021, 2, 1),
-            date(2022, 2, 5),
-            date(2022, 2, 7),
-        ]:
-            self.assertIn(dt, self.holidays)
-        self.holidays.observed = False
+        self.assertHoliday(f"{year}-02-05" for year in range(1917, 2006))
+        self.assertNoHoliday(f"{year}-02-05" for year in range(1900, 1917))
+        self.assertNoHolidayName(
+            "Día de la Constitución [Constitution Day]",
+            Mexico(years=range(1900, 1917)),
+        )
+        self.assertHoliday(
+            "2006-02-06",
+            "2007-02-05",
+            "2008-02-04",
+            "2009-02-02",
+            "2010-02-01",
+            "2011-02-07",
+            "2012-02-06",
+            "2013-02-04",
+            "2014-02-03",
+            "2015-02-02",
+            "2016-02-01",
+            "2017-02-06",
+            "2018-02-05",
+            "2019-02-04",
+            "2020-02-03",
+            "2021-02-01",
+            "2022-02-07",
+            "2023-02-06",
+        )
 
     def test_benito_juarez(self):
-        for dt in [
-            date(2005, 3, 21),
-            date(2006, 3, 21),
-            date(2007, 3, 21),
-            date(2008, 3, 21),
-            date(2009, 3, 21),
-            date(2010, 3, 21),
-            date(2015, 3, 21),
-            date(2016, 3, 21),
-            date(2020, 3, 21),
-            date(2021, 3, 21),
-            date(2022, 3, 21),
-            date(2024, 3, 21),
-        ]:
-            self.assertIn(dt, self.holidays)
-            self.assertNotIn(dt + td(days=-1), self.holidays)
-            self.assertNotIn(dt + td(days=+1), self.holidays)
-        self.holidays.observed = True
-        for dt in [
-            date(2005, 3, 21),
-            date(2006, 3, 21),
-            date(2007, 3, 21),
-            date(2007, 3, 19),
-            date(2008, 3, 21),
-            date(2008, 3, 17),
-            date(2009, 3, 21),
-            date(2009, 3, 16),
-            date(2010, 3, 21),
-            date(2010, 3, 15),
-            date(2015, 3, 21),
-            date(2015, 3, 16),
-            date(2016, 3, 21),
-            date(2020, 3, 21),
-            date(2020, 3, 16),
-            date(2021, 3, 21),
-            date(2021, 3, 15),
-            date(2022, 3, 21),
-            date(2024, 3, 21),
-            date(2024, 3, 18),
-        ]:
-            self.assertIn(dt, self.holidays)
-        self.holidays.observed = False
+        self.assertHoliday(f"{year}-03-21" for year in range(1917, 2007))
+        self.assertNoHoliday(f"{year}-03-21" for year in range(1900, 1917))
+        self.assertNoHolidayName(
+            "Natalicio de Benito Juárez [Benito Juárez's birthday]",
+            Mexico(years=range(1900, 1917)),
+        )
+        self.assertHoliday(
+            "2007-03-19",
+            "2008-03-17",
+            "2009-03-16",
+            "2010-03-15",
+            "2011-03-21",
+            "2012-03-19",
+            "2013-03-18",
+            "2014-03-17",
+            "2015-03-16",
+            "2016-03-21",
+            "2017-03-20",
+            "2018-03-19",
+            "2019-03-18",
+            "2020-03-16",
+            "2021-03-15",
+            "2022-03-21",
+            "2023-03-20",
+        )
 
-    def test_labor_day(self):
-        self.assertNotIn(date(2010, 4, 30), self.holidays)
-        self.assertNotIn(date(2011, 5, 2), self.holidays)
-        self.assertNotIn(date(2022, 5, 2), self.holidays)
-        self.holidays.observed = True
-        self.assertIn(date(2010, 4, 30), self.holidays)
-        self.assertIn(date(2011, 5, 2), self.holidays)
-        self.assertIn(date(2022, 5, 2), self.holidays)
-        self.holidays.observed = False
-        self.assertNotIn(date(1922, 5, 1), self.holidays)
-        for year in range(1923, 2100):
-            dt = date(year, 5, 1)
-            self.assertIn(dt, self.holidays)
-            self.assertNotIn(dt + td(days=-1), self.holidays)
-            self.assertNotIn(dt + td(days=+1), self.holidays)
+    def test_labour_day(self):
+        self.assertHoliday(f"{year}-05-01" for year in range(1923, 2100))
+        self.assertNoHoliday(f"{year}-05-01" for year in range(1900, 1923))
+        self.assertNoHolidayName(
+            "Día del Trabajo [Labour Day]",
+            Mexico(years=range(1900, 1923)),
+        )
 
     def test_independence_day(self):
-        self.assertNotIn(date(2006, 9, 15), self.holidays)
-        self.assertNotIn(date(2007, 9, 17), self.holidays)
-        self.holidays.observed = True
-        self.assertIn(date(2006, 9, 15), self.holidays)
-        self.assertIn(date(2007, 9, 17), self.holidays)
-        self.holidays.observed = False
-        for year in range(1900, 2100):
-            dt = date(year, 9, 16)
-            self.assertIn(dt, self.holidays)
-            self.assertNotIn(dt + td(days=-1), self.holidays)
-            self.assertNotIn(dt + td(days=+1), self.holidays)
+        self.assertHoliday(f"{year}-09-16" for year in range(1900, 2100))
 
     def test_revolution_day(self):
-        for dt in [
-            date(2005, 11, 20),
-            date(2006, 11, 20),
-            date(2007, 11, 20),
-            date(2008, 11, 20),
-            date(2009, 11, 20),
-            date(2010, 11, 20),
-            date(2015, 11, 20),
-            date(2016, 11, 20),
-            date(2020, 11, 20),
-            date(2021, 11, 20),
-            date(2022, 11, 20),
-            date(2023, 11, 20),
-        ]:
-            self.assertIn(dt, self.holidays)
-            self.assertNotIn(dt + td(days=-1), self.holidays)
-            self.assertNotIn(dt + td(days=+1), self.holidays)
-        self.holidays.observed = True
-        for dt in [
-            date(2005, 11, 20),
-            date(2006, 11, 20),
-            date(2007, 11, 19),
-            date(2008, 11, 17),
-            date(2009, 11, 16),
-            date(2010, 11, 15),
-            date(2015, 11, 16),
-            date(2016, 11, 21),
-            date(2020, 11, 16),
-        ]:
-            self.assertIn(dt, self.holidays)
-        self.holidays.observed = False
+        self.assertHoliday(f"{year}-11-20" for year in range(1917, 2006))
+        self.assertNoHoliday(f"{year}-11-20" for year in range(1900, 1917))
+        self.assertNoHolidayName(
+            "Día de la Revolución [Revolution Day]",
+            Mexico(years=range(1900, 1917)),
+        )
+        self.assertHoliday(
+            "2006-11-20",
+            "2007-11-19",
+            "2008-11-17",
+            "2009-11-16",
+            "2010-11-15",
+            "2011-11-21",
+            "2012-11-19",
+            "2013-11-18",
+            "2014-11-17",
+            "2015-11-16",
+            "2016-11-21",
+            "2017-11-20",
+            "2018-11-19",
+            "2019-11-18",
+            "2020-11-16",
+            "2021-11-15",
+            "2022-11-21",
+            "2023-11-20",
+        )
 
     def test_change_of_government(self):
-        self.assertNotIn(date(2012, 11, 30), self.holidays)
-        self.assertNotIn(date(2024, 12, 2), self.holidays)
-        self.holidays.observed = True
-        self.assertIn(date(2012, 11, 30), self.holidays)
-        self.assertIn(date(2024, 12, 2), self.holidays)
-        self.holidays.observed = False
-        for year in range(1950, 2100):
-            dt = date(year, 12, 1)
-            if (year >= 1970) and ((2096 - year) % 6) == 0:
-                self.assertIn(dt, self.holidays)
-                self.assertNotIn(dt + td(days=-1), self.holidays)
-                self.assertNotIn(dt + td(days=+1), self.holidays)
-            else:
-                self.assertNotIn(dt, self.holidays)
+        self.assertHoliday(
+            "1970-12-01",
+            "1976-12-01",
+            "1982-12-01",
+            "1988-12-01",
+            "1994-12-01",
+            "2000-12-01",
+            "2006-12-01",
+            "2012-12-01",
+            "2018-12-01",
+            "2024-12-01",
+        )
+        self.assertNoHoliday(
+            f"{year}-12-01"
+            for year in range(1970, 2100)
+            if (year - 1970) % 6 > 0
+        )
+        name = (
+            "Transmisión del Poder Ejecutivo Federal"
+            " [Change of Federal Government]"
+        )
+        self.assertNoHolidayName(
+            name,
+            Mexico(years=range(1900, 1970)),
+        )
+        self.assertNoHolidayName(
+            name,
+            Mexico(
+                years=(
+                    year for year in range(1970, 2100) if (year - 1970) % 6 > 0
+                )
+            ),
+        )
 
-    def test_christmas(self):
-        for year in range(1900, 2100):
-            dt = date(year, 12, 25)
-            self.assertIn(dt, self.holidays)
-            self.assertNotIn(dt + td(days=-1), self.holidays)
-            self.assertNotIn(dt + td(days=+1), self.holidays)
-        self.assertNotIn(date(2010, 12, 24), self.holidays)
-        self.assertNotIn(date(2016, 12, 26), self.holidays)
-        self.holidays.observed = True
-        self.assertIn(date(2010, 12, 24), self.holidays)
-        self.assertIn(date(2016, 12, 26), self.holidays)
+    def test_christmas_day(self):
+        self.assertHoliday(f"{year}-12-25" for year in range(1900, 2100))
diff --git a/tests/countries/test_monaco.py b/tests/countries/test_monaco.py
index f4c4df306..971ae07ed 100644
--- a/tests/countries/test_monaco.py
+++ b/tests/countries/test_monaco.py
@@ -9,13 +9,14 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-from holidays.countries.monaco import MC, MCO, Monaco
+from holidays.countries.monaco import Monaco, MC, MCO
 from tests.common import TestCase
 
 
 class TestMonaco(TestCase):
-    def setUp(self):
-        self.holidays = Monaco()
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Monaco)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Monaco, MC, MCO)
@@ -49,8 +50,8 @@ def test_observed(self):
             "2023-01-02",
             "2023-11-20",
         )
-        self.assertHoliday(Monaco(observed=True), observed_holidays)
-        self.assertNoHoliday(Monaco(observed=False), observed_holidays)
+        self.assertHoliday(observed_holidays)
+        self.assertNoNonObservedHoliday(observed_holidays)
 
     def test_2020(self):
         self.assertHolidayDates(
@@ -121,3 +122,43 @@ def test_2023(self):
             "2023-12-08",
             "2023-12-25",
         )
+
+    def test_l10n_default(self):
+        def run_tests(languages):
+            for language in languages:
+                mc = Monaco(language=language)
+                self.assertEqual(mc["2022-01-01"], "Le jour de l'An")
+                self.assertEqual(mc["2022-12-25"], "Noël")
+
+        run_tests((Monaco.default_language, None, "invalid"))
+
+        self.set_language("en_US")
+        run_tests((Monaco.default_language,))
+
+    def test_l10n_en_us(self):
+        en_us = "en_US"
+
+        mc = Monaco(language=en_us)
+        self.assertEqual(mc["2015-01-07"], "Public holiday")
+        self.assertEqual(mc["2022-01-01"], "New Year's Day")
+        self.assertEqual(mc["2022-12-25"], "Christmas Day")
+
+        self.set_language(en_us)
+        for language in (None, en_us, "invalid"):
+            mc = Monaco(language=language)
+            self.assertEqual(mc["2022-01-01"], "New Year's Day")
+            self.assertEqual(mc["2022-12-25"], "Christmas Day")
+
+    def test_l10n_uk(self):
+        uk = "uk"
+
+        mc = Monaco(language=uk)
+        self.assertEqual(mc["2015-01-07"], "Державне свято")
+        self.assertEqual(mc["2022-01-01"], "Новий рік")
+        self.assertEqual(mc["2022-12-25"], "Різдво Христове")
+
+        self.set_language(uk)
+        for language in (None, uk, "invalid"):
+            mc = Monaco(language=language)
+            self.assertEqual(mc["2022-01-01"], "Новий рік")
+            self.assertEqual(mc["2022-12-25"], "Різдво Христове")
diff --git a/tests/countries/test_mozambique.py b/tests/countries/test_mozambique.py
index 6e0402c5b..412a73daa 100644
--- a/tests/countries/test_mozambique.py
+++ b/tests/countries/test_mozambique.py
@@ -14,8 +14,9 @@
 
 
 class TestMozambique(TestCase):
-    def setUp(self):
-        self.holidays = Mozambique()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Mozambique)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Mozambique, MZ, MOZ)
@@ -84,4 +85,4 @@ def test_observed(self):
             "2023-06-26",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Mozambique(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
diff --git a/tests/countries/test_namibia.py b/tests/countries/test_namibia.py
index 0b3dac91f..878be2722 100644
--- a/tests/countries/test_namibia.py
+++ b/tests/countries/test_namibia.py
@@ -14,8 +14,9 @@
 
 
 class TestNamibia(TestCase):
-    def setUp(self):
-        self.holidays = Namibia()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Namibia)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Namibia, NA, NAM)
@@ -93,4 +94,4 @@ def test_observed(self):
             "2023-09-11",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Namibia(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
diff --git a/tests/countries/test_new_zealand.py b/tests/countries/test_new_zealand.py
index 9072e6287..be26160ed 100644
--- a/tests/countries/test_new_zealand.py
+++ b/tests/countries/test_new_zealand.py
@@ -325,11 +325,13 @@ def test_christmas_day(self):
             self.assertNotIn(dt + td(days=-1), self.holidays)
         self.assertNotIn(date(2010, 12, 24), self.holidays)
         self.assertNotEqual(
-            self.holidays[date(2011, 12, 26)], "Christmas Day (Observed)"
+            self.holidays[date(2011, 12, 26)],
+            "Christmas Day (Observed)",
         )
         self.holidays.observed = True
         self.assertEqual(
-            self.holidays[date(2011, 12, 27)], "Christmas Day (Observed)"
+            self.holidays[date(2011, 12, 27)],
+            "Christmas Day (Observed)",
         )
         for year, day in enumerate(
             [
diff --git a/tests/countries/test_nigeria.py b/tests/countries/test_nigeria.py
index 2281c6cde..3cc2a4f86 100644
--- a/tests/countries/test_nigeria.py
+++ b/tests/countries/test_nigeria.py
@@ -9,38 +9,159 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import unittest
-from datetime import date
-
-import holidays
-
-
-class TestNigeria(unittest.TestCase):
-    def setUp(self):
-        self.holidays = holidays.Nigeria()
-
-    def test_not_holiday(self):
-        self.assertNotIn(date(1966, 1, 1), self.holidays)
-        self.assertNotIn(date(1980, 5, 1), self.holidays)
-        self.assertNotIn(date(2019, 5, 29), self.holidays)
-        self.assertNotIn(date(1999, 5, 29), self.holidays)
-        self.assertNotIn(date(1999, 6, 12), self.holidays)
-
-    def test_fixed_holidays(self):
-        self.assertIn(date(2015, 5, 29), self.holidays)
-        self.assertIn(date(2019, 1, 1), self.holidays)
-        self.assertIn(date(2019, 5, 1), self.holidays)
-        self.assertIn(date(2019, 6, 12), self.holidays)
-        self.assertIn(date(2019, 10, 1), self.holidays)
-        self.assertIn(date(2019, 12, 25), self.holidays)
-        self.assertIn(date(2019, 12, 26), self.holidays)
-        self.assertIn(date(2020, 6, 12), self.holidays)
-        self.assertIn(date(2021, 6, 14), self.holidays)
-
-    def test_not_observed(self):
-        self.holidays = holidays.Nigeria(observed=False)
-        self.assertNotIn(date(2017, 1, 2), self.holidays)
-        self.assertNotIn(date(2017, 10, 2), self.holidays)
-        self.assertNotIn(date(2019, 8, 13), self.holidays)
-        self.assertNotIn(date(2020, 12, 28), self.holidays)
-        self.assertNotIn(date(2021, 5, 3), self.holidays)
+from holidays.countries.nigeria import Nigeria, NG, NGA
+from tests.common import TestCase
+
+
+class TestNigeria(TestCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Nigeria)
+
+    def test_country_aliases(self):
+        self.assertCountryAliases(Nigeria, NG, NGA)
+
+    def test_no_holidays(self):
+        self.assertNoHolidays(Nigeria(years=1978))
+
+    def test_special_holidays(self):
+        self.assertHoliday(
+            "2019-02-22",
+            "2019-05-29",
+        )
+
+    def test_new_year_day(self):
+        self.assertHoliday(f"{year}-01-01" for year in range(1979, 2050))
+
+    def test_workers_day(self):
+        self.assertHoliday(f"{year}-05-01" for year in range(1981, 2050))
+        self.assertNoHoliday(f"{year}-05-01" for year in range(1979, 1981))
+        self.assertNoHolidayName(
+            "Workers' Day", Nigeria(years=range(1979, 1981))
+        )
+
+    def test_democracy_day(self):
+        self.assertHoliday(f"{year}-05-29" for year in range(2000, 2019))
+        self.assertHoliday(f"{year}-06-12" for year in range(2019, 2050))
+        # in 2019 May 29 is special holiday, so check from 2020
+        self.assertNoHoliday(f"{year}-05-29" for year in range(2020, 2050))
+        self.assertNoHoliday(f"{year}-06-12" for year in range(2000, 2019))
+        self.assertNoHolidayName(
+            "Democracy Day", Nigeria(years=range(1979, 2000))
+        )
+
+    def test_independence_day(self):
+        self.assertHoliday(f"{year}-10-01" for year in range(1979, 2050))
+
+    def test_christmas_day(self):
+        self.assertHoliday(f"{year}-12-25" for year in range(1979, 2050))
+
+    def test_boxing_day(self):
+        self.assertHoliday(f"{year}-12-26" for year in range(1979, 2050))
+
+    def test_easter_based(self):
+        self.assertHoliday(
+            # Good Friday
+            "2018-03-30",
+            "2019-04-19",
+            "2020-04-10",
+            "2021-04-02",
+            "2022-04-15",
+            "2023-04-07",
+            # Easter Monday
+            "2018-04-02",
+            "2019-04-22",
+            "2020-04-13",
+            "2021-04-05",
+            "2022-04-18",
+            "2023-04-10",
+        )
+
+    def test_hijri_based(self):
+        for dt in (
+            "2018-06-15",
+            "2018-06-16",
+            "2019-06-04",
+            "2019-06-05",
+            "2020-05-24",
+            "2020-05-25",
+            "2021-05-13",
+            "2021-05-14",
+            "2022-05-02",
+            "2022-05-03",
+            "2023-04-21",
+            "2023-04-22",
+        ):
+            self.assertIn("Eid-el-Fitr", self.holidays[dt])
+
+        for dt in (
+            "2006-01-10",
+            "2006-01-11",
+            "2006-12-31",
+            "2007-01-01",
+            "2018-08-21",
+            "2018-08-22",
+            "2019-08-11",
+            "2019-08-12",
+            "2020-07-31",
+            "2020-08-01",
+            "2021-07-20",
+            "2021-07-21",
+            "2022-07-09",
+            "2022-07-10",
+            "2023-06-28",
+            "2023-06-29",
+        ):
+            self.assertIn("Eid-el-Kabir", self.holidays[dt])
+
+        for dt in (
+            "2018-11-20",
+            "2019-11-09",
+            "2020-10-29",
+            "2021-10-18",
+            "2022-10-08",
+            "2023-09-27",
+        ):
+            self.assertIn("Eid-el-Mawlid", self.holidays[dt])
+
+    def test_observed(self):
+        dt = (
+            # New Year's Day
+            "2017-01-02",
+            "2022-01-03",
+            "2023-01-02",
+            # Workers' Day
+            "2016-05-02",
+            "2021-05-03",
+            "2022-05-04",
+            # Democracy Day
+            "2016-05-30",
+            "2021-06-14",
+            "2022-06-13",
+            # Independence Day
+            "2016-10-03",
+            "2017-10-02",
+            "2022-10-03",
+            "2023-10-02",
+            # Christmas Day
+            "2016-12-27",
+            "2021-12-27",
+            "2022-12-27",
+            # Boxing Day
+            "2020-12-28",
+            "2021-12-28",
+            # Id el Fitr
+            "2018-06-18",
+            "2020-05-26",
+            "2023-04-24",
+            # Id el Kabir
+            "2019-08-13",
+            "2020-08-03",
+            "2022-07-11",
+            "2022-07-12",
+            # Id el Maulud
+            "2019-11-11",
+            "2022-10-10",
+        )
+        self.assertHoliday(dt)
+        self.assertNoNonObservedHoliday(dt)
diff --git a/tests/countries/test_panama.py b/tests/countries/test_panama.py
index e5fc3ff4a..39ae9154d 100644
--- a/tests/countries/test_panama.py
+++ b/tests/countries/test_panama.py
@@ -9,13 +9,14 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-from holidays.countries.panama import PA, PAN, Panama
+from holidays.countries.panama import Panama, PA, PAN
 from tests.common import TestCase
 
 
 class TestPanama(TestCase):
-    def setUp(self):
-        self.holidays = Panama()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Panama)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Panama, PA, PAN)
@@ -76,7 +77,7 @@ def test_observed(self):
             "2023-01-02",
         )
         self.assertHoliday(observed_holidays)
-        self.assertNoHoliday(Panama(observed=False), observed_holidays)
+        self.assertNoNonObservedHoliday(observed_holidays)
 
     def test_2022(self):
         self.assertHolidays(
diff --git a/tests/countries/test_paraguay.py b/tests/countries/test_paraguay.py
index 3062022e0..d5f91485f 100644
--- a/tests/countries/test_paraguay.py
+++ b/tests/countries/test_paraguay.py
@@ -9,16 +9,20 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import unittest
 from datetime import date
 from datetime import timedelta as td
 
-import holidays
+from holidays.countries.paraguay import Paraguay, PY, PRY
+from tests.common import TestCase
 
 
-class TestParaguay(unittest.TestCase):
-    def setUp(self):
-        self.holidays = holidays.PY()
+class TestParaguay(TestCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Paraguay)
+
+    def test_country_aliases(self):
+        self.assertCountryAliases(Paraguay, PY, PRY)
 
     def test_fixed_holidays(self):
         for year, month, day in (
@@ -40,9 +44,8 @@ def test_fixed_holidays(self):
         ):
             self.assertIn(date(year, month, day), self.holidays)
 
-    def test_no_observed(self):
+    def test_non_observed(self):
         # no observed dates
-        self.holidays.observed = False
         for year, month, day in (
             (2017, 1, 1),
             (2014, 3, 2),
@@ -54,7 +57,7 @@ def test_no_observed(self):
             (2018, 9, 29),
             (2018, 12, 8),
         ):
-            self.assertNotIn(date(year, month, day), self.holidays)
+            self.assertNoNonObservedHoliday(date(year, month, day))
 
     def test_moveable(self):
         for year, month, day in (
diff --git a/tests/countries/test_peru.py b/tests/countries/test_peru.py
index 9d1e0bb93..223c0878c 100644
--- a/tests/countries/test_peru.py
+++ b/tests/countries/test_peru.py
@@ -9,26 +9,88 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import unittest
-from datetime import date
+from holidays.countries.peru import Peru, PE, PER
+from tests.common import TestCase
 
-import holidays
 
+class TestPeru(TestCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Peru)
 
-class TestPeru(unittest.TestCase):
-    def setUp(self):
-        self.holidays = holidays.Peru()
+    def test_country_aliases(self):
+        self.assertCountryAliases(Peru, PE, PER)
 
     def test_2019(self):
-        # No laborables (sector público) not included
-        self.assertIn(date(2019, 1, 1), self.holidays)
-        self.assertIn(date(2019, 4, 18), self.holidays)
-        self.assertIn(date(2019, 4, 19), self.holidays)
-        self.assertIn(date(2019, 5, 1), self.holidays)
-        self.assertIn(date(2019, 6, 29), self.holidays)
-        self.assertIn(date(2019, 7, 29), self.holidays)
-        self.assertIn(date(2019, 8, 30), self.holidays)
-        self.assertIn(date(2019, 10, 8), self.holidays)
-        self.assertIn(date(2019, 11, 1), self.holidays)
-        self.assertIn(date(2019, 12, 8), self.holidays)
-        self.assertIn(date(2019, 12, 25), self.holidays)
+        self.assertHolidayDates(
+            "2019-01-01",
+            "2019-04-18",
+            "2019-04-19",
+            "2019-04-21",
+            "2019-05-01",
+            "2019-06-29",
+            "2019-07-28",
+            "2019-07-29",
+            "2019-08-30",
+            "2019-10-08",
+            "2019-11-01",
+            "2019-12-08",
+            "2019-12-25",
+        )
+
+    def test_2022(self):
+        self.assertHolidayDates(
+            "2022-01-01",
+            "2022-04-14",
+            "2022-04-15",
+            "2022-04-17",
+            "2022-05-01",
+            "2022-06-29",
+            "2022-07-28",
+            "2022-07-29",
+            "2022-08-06",
+            "2022-08-30",
+            "2022-10-08",
+            "2022-11-01",
+            "2022-12-08",
+            "2022-12-09",
+            "2022-12-25",
+        )
+
+    def test_l10n_default(self):
+        def run_tests(languages):
+            for language in languages:
+                pe = Peru(language=language)
+                self.assertEqual(pe["2022-01-01"], "Año Nuevo")
+                self.assertEqual(pe["2022-12-25"], "Navidad del Señor")
+
+        run_tests((Peru.default_language, None, "invalid"))
+
+        self.set_language("en_US")
+        run_tests((Peru.default_language,))
+
+    def test_l10n_en_us(self):
+        en_us = "en_US"
+
+        pe = Peru(language=en_us)
+        self.assertEqual(pe["2018-01-01"], "New Year's Day")
+        self.assertEqual(pe["2022-12-25"], "Christmas Day")
+
+        self.set_language(en_us)
+        for language in (None, en_us, "invalid"):
+            pe = Peru(language=language)
+            self.assertEqual(pe["2018-01-01"], "New Year's Day")
+            self.assertEqual(pe["2022-12-25"], "Christmas Day")
+
+    def test_l10n_uk(self):
+        uk = "uk"
+
+        pe = Peru(language=uk)
+        self.assertEqual(pe["2022-01-01"], "Новий рік")
+        self.assertEqual(pe["2022-12-25"], "Різдво Христове")
+
+        self.set_language(uk)
+        for language in (None, uk, "invalid"):
+            pe = Peru(language=language)
+            self.assertEqual(pe["2022-01-01"], "Новий рік")
+            self.assertEqual(pe["2022-12-25"], "Різдво Христове")
diff --git a/tests/countries/test_saudi_arabia.py b/tests/countries/test_saudi_arabia.py
index d18503dbe..6746f51c4 100644
--- a/tests/countries/test_saudi_arabia.py
+++ b/tests/countries/test_saudi_arabia.py
@@ -9,210 +9,163 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import importlib.util
-import unittest
-from datetime import date
-
-import holidays
-
-
-class TestSaudiArabia(unittest.TestCase):
-    def setUp(self):
-        self.holidays = holidays.SA(observed=True)
-
-    def test_2020(self):
-        # Eid al-Fitr Holiday
-        # (skipping 14, and 15 because they are weekends)
-        self.assertIn(date(2021, 5, 12), self.holidays)
-        self.assertIn(date(2021, 5, 13), self.holidays)
-        self.assertIn(date(2021, 5, 16), self.holidays)
-        self.assertIn(date(2021, 5, 17), self.holidays)
-        # Eid al-Fitr Holiday
-        self.assertIn(date(2021, 7, 19), self.holidays)
-        self.assertIn(date(2021, 7, 20), self.holidays)
-        self.assertIn(date(2021, 7, 21), self.holidays)
-        self.assertIn(date(2021, 7, 22), self.holidays)
-        # National day holiday
-        self.assertIn(date(2021, 9, 23), self.holidays)
+from holidays.countries.saudi_arabia import SaudiArabia, SA, SAU
+from tests.common import TestCase
+
+
+class TestSaudiArabia(TestCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(SaudiArabia)
+
+    def test_country_aliases(self):
+        self.assertCountryAliases(SaudiArabia, SA, SAU)
+
+    def test_special_holidays(self):
+        self.assertHoliday("2022-11-23")
+
+    def test_2021(self):
+        self.assertHolidayDates(
+            "2021-05-13",
+            "2021-05-14",
+            "2021-05-15",
+            "2021-05-16",
+            "2021-05-17",
+            "2021-05-18",
+            "2021-07-19",
+            "2021-07-20",
+            "2021-07-21",
+            "2021-07-22",
+            "2021-09-23",
+        )
 
     def test_weekends(self):
         # Weekend changed from (Thursday, Friday) to
         # (Friday, Saturday) at 2013
         # September 23rd, 2010 was Thursday (Weekend)
         # so, observed is Wednesday
-        self.assertIn(date(2010, 9, 22), self.holidays)
-        self.assertIn(date(2010, 9, 23), self.holidays)
-        self.assertNotIn(date(2010, 9, 24), self.holidays)
+        self.assertHoliday("2010-09-22", "2010-09-23")
+        self.assertNoHoliday("2010-09-24")
 
         # September 23rd, 2006 was Friday (Weekend)
         # so, observed is Saturday
-        self.assertNotIn(date(2005, 9, 22), self.holidays)
-        self.assertIn(date(2005, 9, 23), self.holidays)
-        self.assertIn(date(2005, 9, 24), self.holidays)
+        self.assertHoliday("2005-09-23", "2005-09-24")
+        self.assertNoHoliday("2005-09-22")
 
         # September 23rd, 2006 was Saturday (Weekday before 2013)
-        self.assertNotIn(date(2006, 9, 22), self.holidays)
-        self.assertIn(date(2006, 9, 23), self.holidays)
-        self.assertNotIn(date(2006, 9, 24), self.holidays)
+        self.assertHoliday("2006-09-23")
+        self.assertNoHoliday("2006-09-22", "2006-09-24")
 
     def test_national_day(self):
-        self.assertIn(date(2020, 9, 23), self.holidays)
-        # National day started as a holiday on 2005
-        self.assertNotIn(date(2004, 9, 23), self.holidays)
-        self.assertIn(date(2005, 9, 23), self.holidays)
+        self.assertHoliday(f"{year}-09-23" for year in range(2005, 2050))
+        self.assertNoHolidayName(
+            "National Day Holiday", SaudiArabia(years=range(1950, 2005))
+        )
 
     def test_national_day_observed(self):
-        # September 23rd, 2016 was Friday (Weekend)
-        # so, observed is Thursday
-        self.assertIn(date(2016, 9, 22), self.holidays)
-        self.assertIn(date(2016, 9, 23), self.holidays)
-        self.assertNotIn(date(2016, 9, 24), self.holidays)
-
-        # September 23rd, 2017 was Saturday (Weekend)
-        # so, observed is Sunday
-        self.assertNotIn(date(2017, 9, 22), self.holidays)
-        self.assertIn(date(2017, 9, 23), self.holidays)
-        self.assertIn(date(2017, 9, 24), self.holidays)
-
-    def test_national_day_not_observed(self):
-        self.holidays.observed = False
-        self.assertNotIn(date(2016, 9, 22), self.holidays)
-        self.assertNotIn(date(2017, 9, 24), self.holidays)
+        dt = (
+            "2005-09-24",
+            "2010-09-22",
+            "2011-09-24",
+            "2016-09-22",
+            "2017-09-24",
+            "2022-09-22",
+            "2023-09-24",
+        )
+        self.assertHoliday(dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_national_day_overlaps_hijri_holiday(self):
-        # Eid al-Fitr Holiday is on the same day as the
-        # national day, so there is no extra holidays given for it.
-        self.assertIn(date(2074, 2, 22), self.holidays)
+        for dt in (
+            "2009-09-23",
+            "2015-09-23",
+            "2048-09-23",
+            "2074-09-23",
+        ):
+            self.assertNotIn("National Day Holiday", self.holidays[dt])
 
     def test_founding_day(self):
-        self.assertIn(date(2022, 2, 22), self.holidays)
-        self.assertIn(date(2030, 2, 22), self.holidays)
-        # founding day started as a holiday on 2022
-        self.assertNotIn(date(2021, 2, 22), self.holidays)
-        self.assertNotIn(date(2005, 2, 22), self.holidays)
+        self.assertHoliday(f"{year}-02-22" for year in range(2022, 2050))
+        self.assertNoHolidayName(
+            "Founding Day Holiday", SaudiArabia(years=range(1950, 2022))
+        )
 
     def test_founding_day_observed(self):
-        # February 22nd, 2030 is Friday (Weekend)
-        # so, observed is Thursday
-        self.assertIn(date(2030, 2, 21), self.holidays)
-        self.assertIn(date(2030, 2, 22), self.holidays)
-        self.assertNotIn(date(2016, 2, 23), self.holidays)
-
-        # February 22nd, 2031 is Saturday (Weekend)
-        # so, observed is Sunday
-        self.assertNotIn(date(2031, 2, 21), self.holidays)
-        self.assertIn(date(2031, 2, 22), self.holidays)
-        self.assertIn(date(2031, 2, 23), self.holidays)
-
-    def test_founding_day_not_observed(self):
-        self.holidays.observed = False
-        self.assertNotIn(date(2030, 2, 21), self.holidays)
-        self.assertNotIn(date(2031, 2, 23), self.holidays)
+        dt = (
+            "2025-02-23",
+            "2030-02-21",
+            "2031-02-23",
+            "2036-02-21",
+        )
+        self.assertHoliday(dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_founding_day_overlaps_hijri_holiday(self):
-        # Eid al-Fitr Holiday is on the same day as the
-        # founding day, so there is no extra holidays given for it.
-        self.assertIn(date(2061, 2, 22), self.holidays)
+        self.assertNotIn("National Day Holiday", self.holidays["2061-02-22"])
 
     def test_hijri_based(self):
-        if importlib.util.find_spec("hijri_converter"):
-            self.holidays = holidays.SA(years=[2020, 2022])
+        self.assertHoliday(
             # eid al-fitr
-            self.assertIn(date(2022, 5, 1), self.holidays)
-            self.assertIn(date(2022, 5, 2), self.holidays)
-            self.assertIn(date(2022, 5, 3), self.holidays)
-            self.assertIn(date(2022, 5, 4), self.holidays)
-
+            "2021-05-13",
+            "2021-05-14",
+            "2021-05-15",
+            "2021-05-16",
             # eid al-adha
-            self.assertIn(date(2022, 7, 10), self.holidays)
-            self.assertIn(date(2022, 7, 11), self.holidays)
-            self.assertIn(date(2022, 7, 12), self.holidays)
-            self.assertIn(date(2022, 7, 13), self.holidays)
-
+            "2021-07-19",
+            "2021-07-20",
+            "2021-07-21",
+            "2021-07-22",
             # eid al-fitr
-            self.assertIn(date(2020, 5, 23), self.holidays)
-            self.assertIn(date(2020, 5, 24), self.holidays)
-            self.assertIn(date(2020, 5, 25), self.holidays)
-            self.assertIn(date(2020, 5, 26), self.holidays)
-
+            "2022-05-02",
+            "2022-05-03",
+            "2022-05-04",
+            "2022-05-05",
             # eid al-adha
-            self.assertIn(date(2020, 7, 30), self.holidays)
-            self.assertIn(date(2020, 7, 31), self.holidays)
-            self.assertIn(date(2020, 8, 1), self.holidays)
-            self.assertIn(date(2020, 8, 2), self.holidays)
+            "2022-07-08",
+            "2022-07-09",
+            "2022-07-10",
+            "2022-07-11",
+        )
 
     def test_hijri_based_observed(self):
-        if importlib.util.find_spec("hijri_converter"):
-            self.holidays = holidays.SA(years=range(2019, 2023))
+        dt = (
             # observed eid al-fitr
-            self.assertIn(date(2020, 5, 27), self.holidays)
-
-            self.assertIn(date(2019, 6, 8), self.holidays)
-
+            "2018-06-19",
+            "2018-06-20",
+            "2019-06-08",
+            "2021-05-17",
+            "2021-05-18",
+            "2023-04-25",
+            "2023-04-26",
             # osbserved eid al-adha
-            self.assertIn(date(2022, 7, 12), self.holidays)
-            self.assertIn(date(2022, 7, 13), self.holidays)
-
-            self.assertIn(date(2020, 8, 3), self.holidays)
-            self.assertIn(date(2020, 8, 4), self.holidays)
-
-            # self.assertIn(date(2017, 8, 3), self.holidays)
-            # self.assertIn(date(2017, 8, 4), self.holidays)
-
-            # self.assertIn(date(2019, 8, 13), self.holidays)
-            # self.assertIn(date(2019, 8, 14), self.holidays)
-
-            # self.assertIn(date(2017, 8, 6), self.holidays)
-
-    def test_hijri_based_not_observed(self):
-        if importlib.util.find_spec("hijri_converter"):
-            self.holidays = holidays.SA(
-                observed=False, years=range(2014, 2021)
-            )
-            # observed eid al-fitr
-            self.assertNotIn(date(2020, 5, 27), self.holidays)
-
-            self.assertNotIn(date(2016, 7, 10), self.holidays)
-            self.assertNotIn(date(2016, 7, 11), self.holidays)
-
-            self.assertNotIn(date(2018, 6, 18), self.holidays)
-            self.assertNotIn(date(2018, 6, 19), self.holidays)
-
-            self.assertNotIn(date(2019, 6, 9), self.holidays)
-
-            # osbserved eid al-adha
-            self.assertNotIn(date(2014, 10, 8), self.holidays)
-
-            self.assertNotIn(date(2017, 8, 3), self.holidays)
-            self.assertNotIn(date(2017, 8, 4), self.holidays)
-
-            # self.assertNotIn(date(2019, 8, 13), self.holidays)
-            self.assertNotIn(date(2019, 8, 14), self.holidays)
-
-            self.assertNotIn(date(2017, 8, 6), self.holidays)
+            "2019-08-14",
+            "2020-08-03",
+            "2020-08-04",
+            "2022-07-12",
+            "2022-07-13",
+            "2023-07-01",
+        )
+        self.assertHoliday(dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_hijri_based_with_two_holidays_in_one_year(self):
-        """
-        Note: this might be required change if weekend changes
-        took effect in the holiday.SA class (weekend changed
-        on June 28th, 2013), from (Thursdays and Fridays) to
-        (Fridays, Saturdays).
-        Currently, using newest weekend days (Fridays, and Saturdays)
-        """
-        if importlib.util.find_spec("hijri_converter"):
-            self.holidays = holidays.SA(years=[2006])
-            # eid_alfitr
-            # 23rd is a weekend day (Saturday), so there
-            # is a one day shift
-            self.assertIn(date(2006, 10, 23), self.holidays)
-            self.assertIn(date(2006, 10, 24), self.holidays)
-            self.assertIn(date(2006, 10, 25), self.holidays)
-            self.assertIn(date(2006, 10, 26), self.holidays)
+        self.assertHoliday(
+            # eid al-fitr 1 (hijri year 1420)
+            "2000-01-08",
+            "2000-01-09",
+            "2000-01-10",
+            "2000-01-11",
+            # eid al-fitr 2 (hijri year 1421)
+            "2000-12-27",
+            "2000-12-28",
+            "2000-12-29",
+            "2000-12-30",
             # eid al-adha 1 (hijri year 1426)
-            self.assertIn(date(2006, 1, 9), self.holidays)
-            self.assertIn(date(2006, 1, 10), self.holidays)
-            self.assertIn(date(2006, 1, 11), self.holidays)
-            self.assertIn(date(2006, 1, 12), self.holidays)
+            "2006-01-09",
+            "2006-01-10",
+            "2006-01-11",
+            "2006-01-12",
             # eid al-adha 2 (hijri year 1427)
-            # The remaining holidays fall in the next year 2007
-            self.assertIn(date(2006, 12, 31), self.holidays)
+            "2006-12-30",
+            "2006-12-31",
+        )
diff --git a/tests/countries/test_south_korea.py b/tests/countries/test_south_korea.py
index 1def7448e..4ff31f606 100644
--- a/tests/countries/test_south_korea.py
+++ b/tests/countries/test_south_korea.py
@@ -9,22 +9,23 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-import unittest
 import warnings
 from datetime import date
 
-import holidays
+from holidays.countries.south_korea import SouthKorea, KR, KOR, Korea
+from tests.common import TestCase
 
 
-class TestSouthKorea(unittest.TestCase):
-    def setUp(self):
-        self.holidays = holidays.KR()
+class TestSouthKorea(TestCase):
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(SouthKorea)
+
+    def test_country_aliases(self):
+        self.assertCountryAliases(SouthKorea, KR, KOR)
 
     def test_common(self):
-        holidaysNoObserved = holidays.KR(observed=False)
-        self.assertEqual(
-            holidaysNoObserved[date(2019, 1, 1)], "New Year's Day"
-        )
+        self.assertNonObservedHolidaysName("New Year's Day", "2019-01-01")
 
         self.assertNotIn(date(1582, 10, 2), self.holidays)
         self.assertNotIn(date(1582, 11, 14), self.holidays)
@@ -68,7 +69,8 @@ def test_lunar_new_year(self):
             (2028, 1, 27),
         ]:
             self.assertEqual(
-                self.holidays[date(year, month, day)], "Lunar New Year's Day"
+                self.holidays[date(year, month, day)],
+                "Lunar New Year's Day",
             )
 
         for year, month, day in [
@@ -122,7 +124,8 @@ def test_tree_planting_day(self):
             (2005, 4, 5),
         ]:
             self.assertEqual(
-                self.holidays[date(year, month, day)], "Tree Planting Day"
+                self.holidays[date(year, month, day)],
+                "Tree Planting Day",
             )
 
         for year, month, day in [
@@ -137,7 +140,8 @@ def test_childrens_day(self):
             (2018, 5, 5),
         ]:
             self.assertEqual(
-                self.holidays[date(year, month, day)], "Children's Day"
+                self.holidays[date(year, month, day)],
+                "Children's Day",
             )
 
         for year, month, day in [(2018, 5, 7), (2019, 5, 6)]:
@@ -181,7 +185,8 @@ def test_birthday_of_buddha(self):
 
         for year, month, day in [(2001, 5, 1)]:
             self.assertIn(
-                "Birthday of the Buddha", self.holidays[date(year, month, day)]
+                "Birthday of the Buddha",
+                self.holidays[date(year, month, day)],
             )
 
     def test_labour_day(self):
@@ -324,7 +329,8 @@ def test_chuseok(self):
     def test_national_foundation_day(self):
         for year in [1951, 2049]:
             self.assertIn(
-                "National Foundation Day", self.holidays[date(year, 10, 3)]
+                "National Foundation Day",
+                self.holidays[date(year, 10, 3)],
             )
 
         for year, month, day in [(2021, 10, 4)]:
@@ -356,7 +362,6 @@ def test_christmas_day(self):
             )
 
     def test_years_range(self):
-        self.holidays = holidays.KR(years=[2006, 2021])
         for year in [2006, 2021]:
             self.assertIn(self.holidays[date(year, 1, 1)], "New Year's Day")
 
@@ -366,8 +371,8 @@ def test_special_holidays(self):
     def test_korea_deprecation_warning(self):
         warnings.simplefilter("default")
         with self.assertWarns(Warning):
-            holidays.Korea()
+            Korea()
 
         warnings.simplefilter("error")
         with self.assertRaises(Warning):
-            holidays.Korea()
+            Korea()
diff --git a/tests/countries/test_spain.py b/tests/countries/test_spain.py
index 7690cf43a..e950f3ba4 100644
--- a/tests/countries/test_spain.py
+++ b/tests/countries/test_spain.py
@@ -20,8 +20,9 @@
 
 class TestSpain(unittest.TestCase):
     def setUp(self):
-        self.holidays = holidays.ES(observed=False)
-        self.holidays_observed = holidays.ES()
+        self.holidays = holidays.ES()
+        self.holidays_non_observed = holidays.ES(observed=False)
+
         self.prov_holidays = {
             prov: holidays.ES(observed=False, subdiv=prov)
             for prov in holidays.ES.subdivisions
@@ -50,7 +51,7 @@ def test_fix_days_in_2022(self):
             (DEC, 8),
         )
         for m, d in fix_days_whole_country_2022:
-            self.assertIn(date(2022, m, d), self.holidays_observed)
+            self.assertIn(date(2022, m, d), self.holidays)
 
     def test_province_specific_days(self):
         province_days = {
diff --git a/tests/countries/test_thailand.py b/tests/countries/test_thailand.py
index b19f14dbf..253879e96 100644
--- a/tests/countries/test_thailand.py
+++ b/tests/countries/test_thailand.py
@@ -9,15 +9,14 @@
 #  Website: https://github.com/dr-prodigy/python-holidays
 #  License: MIT (see LICENSE file)
 
-from holidays.countries.thailand import TH, THA, Thailand
+from holidays.countries.thailand import Thailand, TH, THA
 from tests.common import TestCase
 
 
 class TestThailand(TestCase):
-    def setUp(self):
-        self.holidays = Thailand()
-        # Checks in lieu not observed until 2030
-        self.holidays_no_observed = Thailand(observed=False)
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Thailand)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Thailand, TH, THA)
@@ -27,48 +26,72 @@ def test_no_holidays(self):
 
     def test_2022(self):
         self.assertHolidays(
-            ("2022-01-01", "New Year's Day"),
-            ("2022-01-03", "New Year's Day (in lieu)"),
-            ("2022-02-16", "Makha Bucha"),
-            ("2022-04-06", "Chakri Memorial Day"),
-            ("2022-04-13", "Songkran Festival"),
-            ("2022-04-14", "Songkran Festival"),
-            ("2022-04-15", "Songkran Festival"),
-            ("2022-05-01", "National Labour Day"),
-            ("2022-05-02", "National Labour Day (in lieu)"),
-            ("2022-05-04", "Coronation Day"),
-            ("2022-05-15", "Visakha Bucha"),
-            ("2022-05-16", "Visakha Bucha (in lieu)"),
-            ("2022-05-17", "Royal Ploughing Ceremony"),
-            ("2022-06-03", "HM Queen Suthida's Birthday"),
-            ("2022-07-13", "Asarnha Bucha"),
-            ("2022-07-14", "Buddhist Lent Day"),
-            ("2022-07-15", "Bridge Public Holiday"),
-            ("2022-07-28", "HM King Maha Vajiralongkorn's Birthday"),
-            ("2022-07-29", "Bridge Public Holiday"),
+            ("2022-01-01", "วันขึ้นปีใหม่"),
+            ("2022-01-03", "ชดเชยวันขึ้นปีใหม่"),
+            ("2022-02-16", "วันมาฆบูชา"),
+            ("2022-04-06", "วันจักรี"),
+            ("2022-04-13", "วันสงกรานต์"),
+            ("2022-04-14", "วันสงกรานต์"),
+            ("2022-04-15", "วันสงกรานต์"),
+            ("2022-05-01", "วันแรงงานแห่งชาติ"),
+            ("2022-05-02", "ชดเชยวันแรงงานแห่งชาติ"),
+            ("2022-05-04", "วันฉัตรมงคล"),
+            ("2022-05-15", "วันวิสาขบูชา"),
+            ("2022-05-16", "ชดเชยวันวิสาขบูชา"),
+            ("2022-05-17", "วันพืชมงคล"),
+            (
+                "2022-06-03",
+                (
+                    "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสุทิดา "
+                    "พัชรสุธาพิมลลักษณ พระบรมราชินี"
+                ),
+            ),
+            ("2022-07-13", "วันอาสาฬหบูชา"),
+            ("2022-07-14", "วันเข้าพรรษา"),
+            ("2022-07-15", "วันหยุดพิเศษ (เพิ่มเติม)"),
+            (
+                "2022-07-28",
+                (
+                    "วันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรเมนทร"
+                    "รามาธิบดีศรีสินทรมหาวชิราลงกรณ พระวชิรเกล้าเจ้าอยู่หัว"
+                ),
+            ),
+            ("2022-07-29", "วันหยุดพิเศษ (เพิ่มเติม)"),
             (
                 "2022-08-12",
-                "HM Queen Sirikit The Queen Mother's Birthday; National Mother's Day",  # noqa: E501
+                (
+                    "วันเฉลิมพระชนมพรรษาสมเด็จพระบรมราชชนนีพันปีหลวง; "
+                    "วันแม่แห่งชาติ"
+                ),
             ),
-            ("2022-10-13", "HM King Bhumibol Adulyadej Memorial Day"),
-            ("2022-10-14", "Bridge Public Holiday"),
-            ("2022-10-23", "Chulalongkorn Memorial Day"),
-            ("2022-10-24", "Chulalongkorn Memorial Day (in lieu)"),
+            (
+                "2022-10-13",
+                (
+                    "วันคล้ายวันสวรรคตพระบาทสมเด็จพระบรมชนกาธิเบศร "
+                    "มหาภูมิพลอดุลยเดชมหาราช บรมนาถบพิตร"
+                ),
+            ),
+            ("2022-10-14", "วันหยุดพิเศษ (เพิ่มเติม)"),
+            ("2022-10-23", "วันปิยมหาราช"),
+            ("2022-10-24", "ชดเชยวันปิยมหาราช"),
             (
                 "2022-12-05",
-                "HM King Bhumibol Adulyadej's Birthday; National Father's Day",
+                (
+                    "วันคล้ายวันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระบรมชนกาธิเบศร "
+                    "มหาภูมิพลอดุลยเดชมหาราช บรมนาถบพิตร; "
+                    "วันชาติ; วันพ่อแห่งชาติ"
+                ),
             ),
-            ("2022-12-10", "Constitution Day"),
-            ("2022-12-12", "Constitution Day (in lieu)"),
-            ("2022-12-30", "Bridge Public Holiday"),
-            ("2022-12-31", "New Year's Eve"),
+            ("2022-12-10", "วันรัฐธรรมนูญ"),
+            ("2022-12-12", "ชดเชยวันรัฐธรรมนูญ"),
+            ("2022-12-30", "วันหยุดพิเศษ (เพิ่มเติม)"),
+            ("2022-12-31", "วันสิ้นปี"),
         )
 
     def test_new_years_day(self):
         self.assertHoliday(f"{year}-01-01" for year in range(1941, 2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2011-01-03",
             "2012-01-02",
             "2017-01-02",
@@ -80,8 +103,7 @@ def test_new_years_day(self):
     def test_chakri_memorial_day(self):
         self.assertHoliday(f"{year}-04-06" for year in range(1941, 2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2013-04-08",
             "2014-04-07",
             "2019-04-08",
@@ -91,7 +113,7 @@ def test_chakri_memorial_day(self):
         )
 
     def test_songkran_festival(self):
-        name = "Songkran Festival"
+        name = "วันสงกรานต์"
 
         self.assertNoHolidayName(name, Thailand(years=1947))
         for year in range(1948, 1954):
@@ -116,8 +138,7 @@ def test_songkran_festival(self):
                 f"{year}-04-13", f"{year}-04-14", f"{year}-04-15"
             )
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2012-04-16",
             "2013-04-16",
             "2017-04-17",
@@ -132,14 +153,13 @@ def test_songkran_festival(self):
         )
 
     def test_national_labour_day(self):
-        name = "National Labour Day"
+        name = "วันแรงงานแห่งชาติ"
 
         self.assertNoHoliday("1973-05-01")
         self.assertNoHolidayName(name, Thailand(years=1973))
         self.assertHoliday(f"{year}-05-01" for year in range(1974, 2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2010-05-03",
             "2011-05-02",
             "2016-05-02",
@@ -149,7 +169,7 @@ def test_national_labour_day(self):
         )
 
     def test_coronation_day(self):
-        name = "Coronation Day"
+        name = "วันฉัตรมงคล"
 
         self.assertNoHoliday("1957-05-05")
         self.assertNoHolidayName(name, Thailand(years=1957))
@@ -157,8 +177,7 @@ def test_coronation_day(self):
         self.assertNoHolidayName(name, Thailand(years=range(2017, 2020)))
         self.assertHoliday(f"{year}-05-04" for year in range(2020, 2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2012-05-07",
             "2013-05-06",
             "2024-05-06",
@@ -167,37 +186,36 @@ def test_coronation_day(self):
         )
 
     def test_queen_suthida_birthday(self):
-        name = "HM Queen Suthida's Birthday"
+        name = (
+            "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสุทิดา "
+            "พัชรสุธาพิมลลักษณ พระบรมราชินี"
+        )
 
         self.assertNoHoliday("2018-06-03")
         self.assertNoHolidayName(name, Thailand(years=2018))
         self.assertHoliday(f"{year}-06-03" for year in range(2019, 2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2023-06-05",
             "2028-06-05",
             "2029-06-04",
         )
 
     def test_national_day(self):
-        name = "National Day"
-
         self.assertHoliday(f"{year}-06-24" for year in range(1941, 1960))
-        self.assertNoHoliday("1960-06-24")
-        self.assertNoHolidayName(name, Thailand(years=1960))
+        self.assertHoliday(f"{year}-12-05" for year in range(1960, 2058))
 
-        # No in lieus during its existense
+        # No in lieus during its existense on June 24th
+        # 1960+ In lieus are same as HM King Bhumibol Adulyadej's Birthday
 
     def test_rama_x_birthday(self):
-        name = "HM King Maha Vajiralongkorn's Birthday"
+        name = "วันเฉลิมพระชนมพรรษา พระบาทสมเด็จพระเจ้าอยู่หัว"
 
         self.assertNoHoliday("2016-07-28")
         self.assertNoHolidayName(name, Thailand(years=2016))
         self.assertHoliday(f"{year}-07-28" for year in range(2017, 2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2018-07-30",
             "2019-07-29",
             "2024-07-29",
@@ -206,8 +224,10 @@ def test_rama_x_birthday(self):
         )
 
     def test_queen_sirikit_birthday(self):
-        name_ix = "HM Queen Sirikit's Birthday"
-        name_x = "HM Queen Sirikit The Queen Mother's Birthday"
+        name_ix = (
+            "วันเฉลิมพระชนมพรรษาสมเด็จพระนางเจ้าสิริกิติ์ พระบรมราชินีนาถ"
+        )
+        name_x = "วันเฉลิมพระชนมพรรษาสมเด็จพระบรมราชชนนีพันปีหลวง"
 
         self.assertNoHoliday("1975-08-12")
         self.assertNoHolidayName(name_ix, Thailand(years=1975))
@@ -220,8 +240,7 @@ def test_queen_sirikit_birthday(self):
         )
         self.assertNoHolidayName(name_ix, Thailand(years=range(2017, 2058)))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2012-08-13",
             "2017-08-14",
             "2018-08-13",
@@ -231,7 +250,7 @@ def test_queen_sirikit_birthday(self):
         )
 
     def test_national_mothers_day(self):
-        name = "National Mother's Day"
+        name = "วันแม่แห่งชาติ"
 
         self.assertNoHolidayName(name, Thailand(years=1949))
         self.assertHolidaysName(
@@ -246,13 +265,27 @@ def test_national_mothers_day(self):
         # In lieus are same as HM Queen Sirikit's Birthday
 
     def test_rama_ix_memorial_day(self):
-        name = "HM King Bhumibol Adulyadej Memorial Day"
-        self.assertHoliday(f"{year}-10-13" for year in range(2017, 2058))
+        name_ix = (
+            "วันคล้ายวันสวรรคตพระบาทสมเด็จพระปรมินทร"
+            "มหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+        )
+        name_x = (
+            "วันคล้ายวันสวรรคตพระบาทสมเด็จพระบรมชนกาธิเบศร "
+            "มหาภูมิพลอดุลยเดชมหาราช บรมนาถบพิตร"
+        )
+
         self.assertNoHoliday("2016-10-13")
-        self.assertNoHolidayName(name, Thailand(years=2016))
+        self.assertNoHolidayName(name_ix, Thailand(years=2016))
+        self.assertHolidaysName(
+            name_ix, (f"{year}-10-13" for year in range(2017, 2019))
+        )
+        self.assertNoHolidayName(name_x, Thailand(years=range(1941, 2019)))
+        self.assertHolidaysName(
+            name_x, (f"{year}-10-13" for year in range(2019, 2058))
+        )
+        self.assertNoHolidayName(name_ix, Thailand(years=range(2019, 2058)))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2018-10-15",
             "2019-10-14",
             "2024-10-14",
@@ -261,13 +294,12 @@ def test_rama_ix_memorial_day(self):
         )
 
     def test_rama_five_memorial_day(self):
-        name = "Chulalongkorn Memorial Day"
+        name = "วันปิยมหาราช"
         self.assertHoliday(f"{year}-10-23" for year in range(1941, 2058))
         self.assertNoHoliday("1910-10-23", "1940-10-23")
         self.assertNoHolidayName(name, Thailand(years=[1910, 1940]))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2010-10-25",
             "2011-10-24",
             "2016-10-24",
@@ -277,14 +309,40 @@ def test_rama_five_memorial_day(self):
         )
 
     def test_rama_ix_birthday(self):
-        name = "HM King Bhumibol Adulyadej's Birthday"
+        name_reign = (
+            "วันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรมินทร"
+            "มหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+        )
+        name_dead = (
+            "วันคล้ายวันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระปรมินทร"
+            "มหาภูมิพลอดุลยเดช บรมนาถบพิตร"
+        )
+        name_great = (
+            "วันคล้ายวันเฉลิมพระชนมพรรษาพระบาทสมเด็จพระบรม"
+            "ชนกาธิเบศร มหาภูมิพลอดุลยเดชมหาราช บรมนาถบพิตร"
+        )
 
         self.assertNoHoliday("1959-12-05")
-        self.assertNoHolidayName(name, Thailand(years=1959))
-        self.assertHoliday(f"{year}-12-05" for year in range(1960, 2058))
+        self.assertNoHolidayName(name_reign, Thailand(years=1959))
+        self.assertNoHolidayName(name_dead, Thailand(years=1959))
+        self.assertNoHolidayName(name_great, Thailand(years=1959))
+        self.assertHolidaysName(
+            name_reign, (f"{year}-12-05" for year in range(1976, 2016))
+        )
+        self.assertNoHolidayName(name_dead, Thailand(years=range(1941, 2016)))
+        self.assertNoHolidayName(name_great, Thailand(years=range(1941, 2016)))
+        self.assertHolidaysName(
+            name_dead, (f"{year}-12-05" for year in range(2016, 2019))
+        )
+        self.assertNoHolidayName(name_reign, Thailand(years=range(2019, 2058)))
+        self.assertNoHolidayName(name_great, Thailand(years=range(2016, 2019)))
+        self.assertHolidaysName(
+            name_great, (f"{year}-12-05" for year in range(2019, 2058))
+        )
+        self.assertNoHolidayName(name_reign, Thailand(years=range(2019, 2058)))
+        self.assertNoHolidayName(name_dead, Thailand(years=range(2019, 2058)))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2010-12-06",
             "2015-12-07",
             "2020-12-07",
@@ -294,7 +352,7 @@ def test_rama_ix_birthday(self):
         )
 
     def test_national_fathers_day(self):
-        name = "National Father's Day"
+        name = "วันพ่อแห่งชาติ"
 
         # This concides with HM King Bhumibol Adulyadej's Birthday
         self.assertNoHolidayName(name, Thailand(years=1979))
@@ -307,8 +365,7 @@ def test_national_fathers_day(self):
     def test_constitution_day(self):
         self.assertHoliday(f"{year}-12-10" for year in range(1941, 2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2011-12-12",
             "2016-12-12",
             "2017-12-11",
@@ -320,8 +377,7 @@ def test_constitution_day(self):
     def test_new_years_eve(self):
         self.assertHoliday(f"{year}-12-31" for year in range(1941, 2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2012-01-03",
             "2017-01-03",
             "2018-01-02",
@@ -331,7 +387,7 @@ def test_new_years_eve(self):
         )
 
     def test_makha_bucha(self):
-        name = "Makha Bucha"
+        name = "วันมาฆบูชา"
 
         dt = (
             "2010-02-28",
@@ -359,8 +415,7 @@ def test_makha_bucha(self):
         self.assertHolidaysName(name, dt)
         self.assertNoHolidayName(name, Thailand(years=2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2010-03-01",
             "2017-02-13",
             "2020-02-10",
@@ -370,7 +425,7 @@ def test_makha_bucha(self):
         )
 
     def test_visakha_bucha(self):
-        name = "Visakha Bucha"
+        name = "วันวิสาขบูชา"
 
         dt = (
             "2010-05-28",
@@ -398,8 +453,7 @@ def test_visakha_bucha(self):
         self.assertHolidaysName(name, dt)
         self.assertNoHolidayName(name, Thailand(years=2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2019-05-20",
             "2022-05-16",
             "2023-06-05",
@@ -409,7 +463,7 @@ def test_visakha_bucha(self):
         )
 
     def test_asarnha_bucha(self):
-        name = "Asarnha Bucha"
+        name = "วันอาสาฬหบูชา"
 
         dt = (
             "2010-07-26",
@@ -437,8 +491,7 @@ def test_asarnha_bucha(self):
         self.assertHolidaysName(name, dt)
         self.assertNoHolidayName(name, Thailand(years=2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2017-07-10",
             "2020-07-07",
             "2021-07-26",
@@ -448,7 +501,7 @@ def test_asarnha_bucha(self):
         )
 
     def test_khao_phansa(self):
-        name = "Buddhist Lent Day"
+        name = "วันเข้าพรรษา"
 
         dt = (
             "2010-07-27",
@@ -476,15 +529,14 @@ def test_khao_phansa(self):
         self.assertHolidaysName(name, dt)
         self.assertNoHolidayName(name, Thailand(years=2058))
 
-        self.assertNoHoliday(
-            self.holidays_no_observed,
+        self.assertNoNonObservedHoliday(
             "2011-07-18",
             "2014-07-14",
             "2018-07-30",
         )
 
     def test_raeknakhwan(self):
-        name = "Royal Ploughing Ceremony"
+        name = "วันพืชมงคล"
         dt = (
             "2011-05-13",
             "2012-05-09",
@@ -508,3 +560,36 @@ def test_raeknakhwan(self):
         )
 
         # No Royal Ploughing Ceremony on weekend for 1997-2023
+
+    def test_l10n_default(self):
+        def run_tests(languages):
+            for language in languages:
+                th_th = Thailand(language=language)
+                self.assertEqual(th_th["2022-01-01"], "วันขึ้นปีใหม่")
+                self.assertEqual(th_th["2022-04-13"], "วันสงกรานต์")
+                self.assertEqual(th_th["2022-05-02"], "ชดเชยวันแรงงานแห่งชาติ")
+                self.assertEqual(th_th["2022-12-10"], "วันรัฐธรรมนูญ")
+
+        run_tests((Thailand.default_language, None, "invalid"))
+
+        self.set_language("en_US")
+        run_tests((Thailand.default_language,))
+
+    def test_l10n_en(self):
+        language = "en_US"
+
+        th_en = Thailand(language=language)
+        self.assertEqual(th_en["2022-01-01"], "New Year's Day")
+        self.assertEqual(th_en["2022-04-13"], "Songkran Festival")
+        self.assertEqual(th_en["2022-05-02"], "National Labour Day (in lieu)")
+        self.assertEqual(th_en["2022-12-10"], "Constitution Day")
+
+        self.set_language(language)
+        for language in (None, language, "invalid"):
+            th_en = Thailand(language=language)
+            self.assertEqual(th_en["2022-01-01"], "New Year's Day")
+            self.assertEqual(th_en["2022-04-13"], "Songkran Festival")
+            self.assertEqual(
+                th_en["2022-05-02"], "National Labour Day (in lieu)"
+            )
+            self.assertEqual(th_en["2022-12-10"], "Constitution Day")
diff --git a/tests/countries/test_ukraine.py b/tests/countries/test_ukraine.py
index 10d9102c3..e2eabf29a 100644
--- a/tests/countries/test_ukraine.py
+++ b/tests/countries/test_ukraine.py
@@ -14,10 +14,6 @@
 
 
 class TestUkraine(TestCase):
-    def setUp(self):
-        super().setUp()
-        self.holidays_no_observed = Ukraine(observed=False)
-
     @classmethod
     def setUpClass(cls):
         super().setUpClass(Ukraine)
@@ -42,7 +38,7 @@ def test_new_year_day(self):
             "2023-01-02",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_christmas_julian_day(self):
         self.assertNoHoliday(f"{year}-01-07" for year in range(1918, 1991))
@@ -60,7 +56,7 @@ def test_christmas_julian_day(self):
             "2024-01-08",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_womens_day(self):
         self.assertNoHoliday(f"{year}-03-08" for year in range(1918, 1966))
@@ -76,7 +72,7 @@ def test_womens_day(self):
             "2025-03-10",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_easter(self):
         name = "Великдень (Пасха)"
@@ -126,7 +122,7 @@ def test_easter(self):
             "2084-05-02",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_trinity(self):
         name = "Трійця"
@@ -167,7 +163,7 @@ def test_trinity(self):
             "2023-06-05",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_labour_day(self):
         name_before = "День міжнародної солідарності трудящих"
@@ -188,7 +184,7 @@ def test_labour_day(self):
             "2022-05-02",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_victory_day(self):
         name = (
@@ -209,7 +205,7 @@ def test_victory_day(self):
             "2021-05-10",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_constitution_day(self):
         self.assertNoHoliday(f"{year}-06-28" for year in range(1918, 1997))
@@ -225,7 +221,7 @@ def test_constitution_day(self):
             "2025-06-30",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_statehood_day(self):
         self.assertNoHoliday(f"{year}-07-28" for year in range(1918, 2022))
@@ -236,7 +232,7 @@ def test_statehood_day(self):
 
         dt = ("2024-07-29",)
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_independence_day(self):
         self.assertNoHoliday(f"{year}-08-24" for year in range(1918, 1992))
@@ -253,7 +249,7 @@ def test_independence_day(self):
             "2019-08-26",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_defenders_day(self):
         name_before = "День захисника України"
@@ -270,7 +266,7 @@ def test_defenders_day(self):
             "2023-10-16",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_october_revolution_day(self):
         self.assertHoliday(f"{year}-11-07" for year in range(1918, 2000))
@@ -287,7 +283,7 @@ def test_october_revolution_day(self):
             "1999-11-09",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_christmas_gregorian_day(self):
         self.assertNoHoliday(f"{year}-12-25" for year in range(1918, 2017))
@@ -302,7 +298,7 @@ def test_christmas_gregorian_day(self):
             "2022-12-26",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(self.holidays_no_observed, dt)
+        self.assertNoNonObservedHoliday(dt)
 
     def test_old_holidays(self):
         self.assertHoliday(f"{year}-01-22" for year in range(1918, 1951))
diff --git a/tests/countries/test_united_kingdom.py b/tests/countries/test_united_kingdom.py
index 9f1914e06..2a377a6da 100644
--- a/tests/countries/test_united_kingdom.py
+++ b/tests/countries/test_united_kingdom.py
@@ -150,11 +150,13 @@ def test_christmas_day(self):
             self.assertNotIn(dt + td(days=-1), self.holidays)
         self.assertNotIn(date(2010, 12, 24), self.holidays)
         self.assertNotEqual(
-            self.holidays[date(2011, 12, 26)], "Christmas Day (Observed)"
+            self.holidays[date(2011, 12, 26)],
+            "Christmas Day (Observed)",
         )
         self.holidays.observed = True
         self.assertEqual(
-            self.holidays[date(2011, 12, 27)], "Christmas Day (Observed)"
+            self.holidays[date(2011, 12, 27)],
+            "Christmas Day (Observed)",
         )
         for year, day in enumerate(
             [
diff --git a/tests/countries/test_uruguay.py b/tests/countries/test_uruguay.py
index 3aef0edb7..de78d0719 100644
--- a/tests/countries/test_uruguay.py
+++ b/tests/countries/test_uruguay.py
@@ -58,7 +58,8 @@ def test_jura_de_la_constitucion_day(self):
             self.assertNotIn(dt + td(days=-1), self.holidays)
             self.assertNotIn(dt + td(days=+1), self.holidays)
             self.assertEqual(
-                self.holidays[dt], "Jura de la Constitución [Constitution Day]"
+                self.holidays[dt],
+                "Jura de la Constitución [Constitution Day]",
             )
 
     def test_declaratoria_de_la_independencia_day(self):
@@ -68,7 +69,8 @@ def test_declaratoria_de_la_independencia_day(self):
             self.assertNotIn(dt + td(days=-1), self.holidays)
             self.assertNotIn(dt + td(days=+1), self.holidays)
             self.assertEqual(
-                self.holidays[dt], "Día de la Independencia [Independence Day]"
+                self.holidays[dt],
+                "Día de la Independencia [Independence Day]",
             )
 
     def test_christmas(self):
@@ -78,7 +80,8 @@ def test_christmas(self):
             self.assertNotIn(dt + td(days=-1), self.holidays)
             self.assertNotIn(dt + td(days=+1), self.holidays)
             self.assertEqual(
-                self.holidays[dt], "Día de la Familia [Day of the Family]"
+                self.holidays[dt],
+                "Día de la Familia [Day of the Family]",
             )
 
     # Partially paid holidays.
@@ -111,7 +114,8 @@ def test_dia_de_los_difuntos_day(self):
             self.assertNotIn(dt + td(days=-1), self.holidays)
             self.assertNotIn(dt + td(days=+1), self.holidays)
             self.assertEqual(
-                self.holidays[dt], "Día de los Difuntos [All Souls' Day]"
+                self.holidays[dt],
+                "Día de los Difuntos [All Souls' Day]",
             )
 
     # Moveable holidays.
diff --git a/tests/countries/test_vietnam.py b/tests/countries/test_vietnam.py
index f6f9a37e9..3990a51bc 100644
--- a/tests/countries/test_vietnam.py
+++ b/tests/countries/test_vietnam.py
@@ -17,8 +17,9 @@
 
 
 class TestVietnam(TestCase):
-    def setUp(self):
-        self.holidays = Vietnam()
+    @classmethod
+    def setUpClass(self):
+        super().setUpClass(Vietnam)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Vietnam, VN, VNM)
@@ -135,7 +136,6 @@ def test_observed(self):
         )
 
     def test_not_observed(self):
-        self.assertNoHoliday(
-            Vietnam(observed=False),
+        self.assertNoNonObservedHoliday(
             "2023-01-02",
         )
diff --git a/tests/countries/test_zambia.py b/tests/countries/test_zambia.py
index 9886fee3e..8f4b0da92 100644
--- a/tests/countries/test_zambia.py
+++ b/tests/countries/test_zambia.py
@@ -14,9 +14,9 @@
 
 
 class TestZambia(TestCase):
-    def setUp(self):
-        self.holidays = Zambia()
-        self.holidays_no_observed = Zambia(observed=False)
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Zambia)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Zambia, ZM, ZMB)
@@ -144,4 +144,4 @@ def test_observed(self):
             "2030-04-29",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Zambia(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
diff --git a/tests/countries/test_zimbabwe.py b/tests/countries/test_zimbabwe.py
index 2d02dfce9..f21298f5d 100644
--- a/tests/countries/test_zimbabwe.py
+++ b/tests/countries/test_zimbabwe.py
@@ -14,9 +14,9 @@
 
 
 class TestZimbabwe(TestCase):
-    def setUp(self):
-        self.holidays = Zimbabwe()
-        self.holidays_no_observed = Zimbabwe(observed=False)
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass(Zimbabwe)
 
     def test_country_aliases(self):
         self.assertCountryAliases(Zimbabwe, ZW, ZWE)
@@ -116,4 +116,4 @@ def test_observed(self):
             "2060-04-20",
         )
         self.assertHoliday(dt)
-        self.assertNoHoliday(Zimbabwe(observed=False), dt)
+        self.assertNoNonObservedHoliday(dt)
diff --git a/tests/financial/test_ny_stock_exchange.py b/tests/financial/test_ny_stock_exchange.py
index daac66f6c..9759ffc0d 100644
--- a/tests/financial/test_ny_stock_exchange.py
+++ b/tests/financial/test_ny_stock_exchange.py
@@ -44,6 +44,17 @@ def test_new_years(self):
             self.assertNotIn(dt + td(days=+1), self.holidays)
             self.assertNotIn(dt + td(days=+7), self.holidays)
 
+        # observed on previous year Dec 31
+        for dt in (
+            date(1994, JAN, 1),
+            date(2000, JAN, 1),
+            date(2005, JAN, 1),
+            date(2011, JAN, 1),
+            date(2022, JAN, 1),
+        ):
+            self.assertNotIn(dt, self.holidays)
+            self.assertIn(dt + td(days=-1), self.holidays)
+
     def test_mlk(self):
         for dt in [
             date(1999, JAN, 18),
diff --git a/tests/test_calendars.py b/tests/test_calendars.py
new file mode 100644
index 000000000..de1218ab1
--- /dev/null
+++ b/tests/test_calendars.py
@@ -0,0 +1,128 @@
+#  python-holidays
+#  ---------------
+#  A fast, efficient Python library for generating country, province and state
+#  specific sets of holidays on the fly. It aims to make determining whether a
+#  specific date is a holiday as fast and flexible as possible.
+#
+#  Authors: dr-prodigy <maurizio.montel@gmail.com> (c) 2017-2022
+#           ryanss <ryanssdev@icloud.com> (c) 2014-2017
+#  Website: https://github.com/dr-prodigy/python-holidays
+#  License: MIT (see LICENSE file)
+
+import unittest
+from datetime import date
+
+from holidays import calendars
+from holidays.calendars import _get_nth_weekday_of_month
+from holidays.constants import FEB, MAR, MAY, JUN, JUL, AUG, OCT
+
+
+class TestThaiLuniSolarCalendar(unittest.TestCase):
+    def setUp(self) -> None:
+        super().setUpClass()
+        self.calendar = calendars._ThaiLuniSolar()
+
+    def test_asarnha_bucha_date(self):
+        asarnha_bucha_year_date = {
+            self.calendar.START_YEAR - 1: None,
+            self.calendar.END_YEAR + 1: None,
+            2022: date(2022, JUL, 13),
+            2023: date(2023, AUG, 1),
+            2024: date(2024, JUL, 20),
+            2025: date(2025, JUL, 10),
+        }
+        for year in asarnha_bucha_year_date:
+            self.assertEqual(
+                asarnha_bucha_year_date[year],
+                self.calendar.asarnha_bucha_date(year),
+            )
+
+    def test_atthami_bucha_date(self):
+        atthami_bucha_year_date = {
+            self.calendar.START_YEAR - 1: None,
+            self.calendar.END_YEAR + 1: None,
+            2022: date(2022, MAY, 23),
+            2023: date(2023, JUN, 11),
+            2024: date(2024, MAY, 30),
+            2025: date(2025, MAY, 19),
+        }
+        for year in atthami_bucha_year_date:
+            self.assertEqual(
+                atthami_bucha_year_date[year],
+                self.calendar.atthami_bucha_date(year),
+            )
+
+    def test_khao_phansa_date(self):
+        khao_phansa_year_date = {
+            self.calendar.START_YEAR - 1: None,
+            self.calendar.END_YEAR + 1: None,
+            2022: date(2022, JUL, 14),
+            2023: date(2023, AUG, 2),
+            2024: date(2024, JUL, 21),
+            2025: date(2025, JUL, 11),
+        }
+        for year in khao_phansa_year_date:
+            self.assertEqual(
+                khao_phansa_year_date[year],
+                self.calendar.khao_phansa_date(year),
+            )
+
+    def test_makha_bucha_date(self):
+        makha_bucha_year_date = {
+            self.calendar.START_YEAR - 1: None,
+            self.calendar.END_YEAR + 1: None,
+            2022: date(2022, FEB, 16),
+            2023: date(2023, MAR, 6),
+            2024: date(2024, FEB, 24),
+            2025: date(2025, FEB, 12),
+        }
+        for year in makha_bucha_year_date:
+            self.assertEqual(
+                makha_bucha_year_date[year],
+                self.calendar.makha_bucha_date(year),
+            )
+
+    def test_ok_phansa_date(self):
+        ok_phansa_year_date = {
+            self.calendar.START_YEAR - 1: None,
+            self.calendar.END_YEAR + 1: None,
+            2022: date(2022, OCT, 10),
+            2023: date(2023, OCT, 29),
+            2024: date(2024, OCT, 17),
+            2025: date(2025, OCT, 7),
+        }
+        for year in ok_phansa_year_date:
+            self.assertEqual(
+                ok_phansa_year_date[year],
+                self.calendar.ok_phansa_date(year),
+            )
+
+    def test_visakha_bucha_date(self):
+        visakha_bucha_year_date = {
+            self.calendar.START_YEAR - 1: None,
+            self.calendar.END_YEAR + 1: None,
+            2022: date(2022, MAY, 15),
+            2023: date(2023, JUN, 3),
+            2024: date(2024, MAY, 22),
+            2025: date(2025, MAY, 11),
+        }
+        for year in visakha_bucha_year_date:
+            self.assertEqual(
+                visakha_bucha_year_date[year],
+                self.calendar.visakha_bucha_date(year),
+            )
+
+
+class TestRelativeWeekdays(unittest.TestCase):
+    def test_weekday_of_month(self):
+        # 1st Monday of 2023 months
+        for month, day in enumerate((3, 7, 7, 4, 2, 6, 4, 1, 5, 3, 7, 5), 1):
+            first_monday = _get_nth_weekday_of_month(1, 1, month, 2023)
+            self.assertEqual(first_monday.day, day)
+
+        # Last Saturday of 2023 months
+        for month, day in enumerate(
+            (28, 25, 25, 29, 27, 24, 29, 26, 30, 28, 25, 30), 1
+        ):
+            last_friday = _get_nth_weekday_of_month(-1, 5, month, 2023)
+            self.assertEqual(last_friday.day, day)
diff --git a/tests/test_holiday_base.py b/tests/test_holiday_base.py
index 16e9580dc..920947f65 100644
--- a/tests/test_holiday_base.py
+++ b/tests/test_holiday_base.py
@@ -75,7 +75,8 @@ def test_getitem(self):
             [date(2014, 1, 1), date(2013, 12, 25)],
         )
         self.assertListEqual(
-            self.holidays[date(2013, 12, 31) : date(2014, 1, 2) : -3], []
+            self.holidays[date(2013, 12, 31) : date(2014, 1, 2) : -3],
+            [],
         )
         self.assertListEqual(
             self.holidays[date(2014, 1, 1) : date(2013, 12, 24) : td(days=3)],
@@ -124,7 +125,8 @@ def test_pop_named(self):
         self.holidays.pop_named("New Year's Day")
         self.assertNotIn(date(2014, 1, 1), self.holidays)
         self.assertRaises(
-            KeyError, lambda: self.holidays.pop_named("New Year's Dayz")
+            KeyError,
+            lambda: self.holidays.pop_named("New Year's Dayz"),
         )
 
     def test_setitem(self):
@@ -328,11 +330,13 @@ def test_add_countries(self):
         self.assertEqual(na.get(date(1969, 7, 1)), "Dominion Day")
         self.assertEqual(na.get(date(1983, 7, 1)), "Canada Day")
         self.assertEqual(
-            na.get(date(1969, 12, 25)), "Christmas Day; Navidad [Christmas]"
+            na.get(date(1969, 12, 25)),
+            "Christmas Day; Navidad [Christmas Day]",
         )
         na = holidays.MX() + holidays.CA() + holidays.US()
         self.assertEqual(
-            na.get(date(1969, 12, 25)), "Christmas Day; Navidad [Christmas]"
+            na.get(date(1969, 12, 25)),
+            "Christmas Day; Navidad [Christmas Day]",
         )
         self.assertEqual(na, na.copy())
 
@@ -380,7 +384,7 @@ def test_get_list(self):
         self.assertIn(date(1969, 12, 25), na)
         self.assertEqual(
             na.get_list(date(1969, 12, 25)),
-            ["Christmas Day", "Navidad [Christmas]"],
+            ["Christmas Day", "Navidad [Christmas Day]"],
         )
         self.assertEqual(na.get_list(date(1969, 7, 1)), ["Dominion Day"])
         self.assertEqual(na.get_list(date(1969, 1, 3)), [])
@@ -463,19 +467,101 @@ def _populate(self, year):
 
         self.assertIn(date(2014, 12, 31), Dec31Holiday())
 
-    def test_get_named(self):
-        us = holidays.UnitedStates(years=[2020])
+    def test_get_named_contains(self):
+        us = holidays.UnitedStates(years=2020)
+
+        holidays_count = len(us.keys())
+        for name in ("New", "Year"):
+            self.assertIn(date(2020, 1, 1), us.get_named(name))
+        for name in ("new", "year", "NEW Year"):
+            self.assertNotIn(
+                date(2020, 1, 1), us.get_named(name, lookup="contains")
+            )
+        self.assertEqual(holidays_count, len(us.keys()))
+
+        us = holidays.UnitedStates(years=2022)
+        self.assertEqual(
+            1, len(us.get_named("Thanksgiving", lookup="contains"))
+        )
+        self.assertEqual(1, len(us.get_named("Thanksgivi", lookup="contains")))
+        self.assertEqual(0, len(us.get_named("thanks", lookup="contains")))
+        self.assertEqual([2022], list(us.years))
+
+        us = holidays.UnitedStates(observed=False, years=2022)
+        self.assertEqual(
+            2, len(us.get_named("Independence Day", lookup="contains"))
+        )
+        self.assertEqual(
+            0, len(us.get_named("independence day", lookup="contains"))
+        )
+
+    def test_get_named_exact(self):
+        us = holidays.UnitedStates(years=2020)
+        holidays_count = len(us.keys())
+        for name in ("New Year's Day", "Christmas Day"):
+            self.assertEqual(1, len(us.get_named(name)))
+        for name in ("New", "Day"):
+            self.assertEqual(0, len(us.get_named(name, lookup="exact")))
+        self.assertEqual(holidays_count, len(us.keys()))
+
+        us = holidays.UnitedStates(years=2022)
+        self.assertEqual(1, len(us.get_named("Thanksgiving", lookup="exact")))
+        self.assertEqual(0, len(us.get_named("thanksgiving", lookup="exact")))
+        self.assertEqual([2022], list(us.years))
+
+        us = holidays.UnitedStates(observed=False, years=2022)
+        self.assertEqual(
+            1, len(us.get_named("Independence Day", lookup="exact"))
+        )
+
+    def test_get_named_icontains(self):
+        us = holidays.UnitedStates(years=2020)
+        holidays_count = len(us.keys())
+        self.assertEqual(holidays_count, len(us.keys()))
+        for name in ("New", "Year", "new", "year", "NEW Year"):
+            self.assertIn(date(2020, 1, 1), us.get_named(name))
+
+        us = holidays.UnitedStates(years=2022)
+        for name in ("Thanksgiving", "thanksgiving", "Thanksgivi"):
+            self.assertEqual(1, len(us.get_named(name, lookup="icontains")))
+        self.assertEqual([2022], list(us.years))
+
+        us = holidays.UnitedStates(observed=False, years=2022)
+        self.assertEqual(
+            2, len(us.get_named("Independence Day", lookup="icontains"))
+        )
+
+    def test_get_named_iexact(self):
+        us = holidays.UnitedStates(years=2020)
         holidays_count = len(us.keys())
-        # check for "New Year's Day" presence in get_named("new")
-        self.assertIn(date(2020, 1, 1), us.get_named("new"))
         self.assertEqual(holidays_count, len(us.keys()))
 
-        # check for searching holiday in US when the observed holiday is on
-        # a different year than input one
-        us = holidays.US(years=[2022])
-        us.get_named("Thanksgiving")
+        for name in ("new year's day", "New Year's Day"):
+            self.assertIn(
+                date(2020, 1, 1), us.get_named(name, lookup="iexact")
+            )
+        for name in ("New Year Day", "New Year", "year", "NEW Year"):
+            self.assertNotIn(
+                date(2020, 1, 1), us.get_named(name, lookup="iexact")
+            )
+
+        us = holidays.UnitedStates(years=2022)
+        self.assertEqual(1, len(us.get_named("thanksgiving", lookup="iexact")))
+        self.assertEqual(0, len(us.get_named("Thanksgivin", lookup="iexact")))
         self.assertEqual([2022], list(us.years))
 
+        us = holidays.UnitedStates(years=2022)
+        self.assertEqual(
+            1, len(us.get_named("independence day", lookup="iexact"))
+        )
+
+    def test_get_named_lookup_invalid(self):
+        us = holidays.UnitedStates(years=2020)
+        self.assertRaises(
+            AttributeError,
+            lambda: us.get_named("Holiday name", lookup="invalid"),
+        )
+
 
 class TestArgs(unittest.TestCase):
     def setUp(self):
@@ -593,12 +679,14 @@ def test_dates(self):
     def test_datetimes(self):
         self.assertIn(datetime(2014, 1, 1, 13, 45), self.holidays)
         self.assertEqual(
-            self.holidays[datetime(2014, 1, 1, 13, 45)], "New Year's Day"
+            self.holidays[datetime(2014, 1, 1, 13, 45)],
+            "New Year's Day",
         )
         self.holidays[datetime(2014, 1, 3, 1, 1)] = "Fake Holiday"
         self.assertIn(datetime(2014, 1, 3, 2, 2), self.holidays)
         self.assertEqual(
-            self.holidays.pop(datetime(2014, 1, 3, 4, 4)), "Fake Holiday"
+            self.holidays.pop(datetime(2014, 1, 3, 4, 4)),
+            "Fake Holiday",
         )
         self.assertNotIn(datetime(2014, 1, 3, 2, 2), self.holidays)
 
@@ -627,11 +715,15 @@ def test_exceptions(self):
             (TypeError, ValueError), lambda: "abc" in self.holidays
         )
         self.assertRaises(
-            (TypeError, ValueError), lambda: self.holidays.get("abc123")
+            (TypeError, ValueError),
+            lambda: self.holidays.get("abc123"),
         )
         self.assertRaises(TypeError, lambda: self.holidays.get({"123"}))
         self.assertRaises(
-            (TypeError, ValueError), self.holidays.__setitem__, "abc", "Test"
+            (TypeError, ValueError),
+            self.holidays.__setitem__,
+            "abc",
+            "Test",
         )
         self.assertRaises((TypeError, ValueError), lambda: {} in self.holidays)
 
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 43285c93d..06f817785 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -14,7 +14,6 @@
 from datetime import date
 
 from holidays import utils
-from holidays.constants import FEB, MAR, MAY, JUN, JUL, AUG, OCT
 
 
 class TestCountryHolidays(unittest.TestCase):
@@ -99,99 +98,3 @@ def test_all_countries(self):
             for year in range(date.today().year - 10, date.today().year + 3):
                 for holiday in utils.country_holidays(country, years=year):
                     self.assertEqual(holiday.year, year)
-
-
-class TestThaiLuniSolarCalendar(unittest.TestCase):
-    def setUp(self) -> None:
-        super().setUpClass()
-        self.calendar = utils._ThaiLuniSolar()
-
-    def test_asarnha_bucha_date(self):
-        asarnha_bucha_year_date = {
-            self.calendar.START_YEAR - 1: None,
-            self.calendar.END_YEAR + 1: None,
-            2022: date(2022, JUL, 13),
-            2023: date(2023, AUG, 1),
-            2024: date(2024, JUL, 20),
-            2025: date(2025, JUL, 10),
-        }
-        for year in asarnha_bucha_year_date:
-            self.assertEqual(
-                asarnha_bucha_year_date[year],
-                self.calendar.asarnha_bucha_date(year),
-            )
-
-    def test_atthami_bucha_date(self):
-        atthami_bucha_year_date = {
-            self.calendar.START_YEAR - 1: None,
-            self.calendar.END_YEAR + 1: None,
-            2022: date(2022, MAY, 23),
-            2023: date(2023, JUN, 11),
-            2024: date(2024, MAY, 30),
-            2025: date(2025, MAY, 19),
-        }
-        for year in atthami_bucha_year_date:
-            self.assertEqual(
-                atthami_bucha_year_date[year],
-                self.calendar.atthami_bucha_date(year),
-            )
-
-    def test_khao_phansa_date(self):
-        khao_phansa_year_date = {
-            self.calendar.START_YEAR - 1: None,
-            self.calendar.END_YEAR + 1: None,
-            2022: date(2022, JUL, 14),
-            2023: date(2023, AUG, 2),
-            2024: date(2024, JUL, 21),
-            2025: date(2025, JUL, 11),
-        }
-        for year in khao_phansa_year_date:
-            self.assertEqual(
-                khao_phansa_year_date[year],
-                self.calendar.khao_phansa_date(year),
-            )
-
-    def test_makha_bucha_date(self):
-        makha_bucha_year_date = {
-            self.calendar.START_YEAR - 1: None,
-            self.calendar.END_YEAR + 1: None,
-            2022: date(2022, FEB, 16),
-            2023: date(2023, MAR, 6),
-            2024: date(2024, FEB, 24),
-            2025: date(2025, FEB, 12),
-        }
-        for year in makha_bucha_year_date:
-            self.assertEqual(
-                makha_bucha_year_date[year],
-                self.calendar.makha_bucha_date(year),
-            )
-
-    def test_ok_phansa_date(self):
-        ok_phansa_year_date = {
-            self.calendar.START_YEAR - 1: None,
-            self.calendar.END_YEAR + 1: None,
-            2022: date(2022, OCT, 10),
-            2023: date(2023, OCT, 29),
-            2024: date(2024, OCT, 17),
-            2025: date(2025, OCT, 7),
-        }
-        for year in ok_phansa_year_date:
-            self.assertEqual(
-                ok_phansa_year_date[year],
-                self.calendar.ok_phansa_date(year),
-            )
-
-    def test_visakha_bucha_date(self):
-        visakha_bucha_year_date = {
-            self.calendar.START_YEAR - 1: None,
-            self.calendar.END_YEAR + 1: None,
-            2022: date(2022, MAY, 15),
-            2023: date(2023, JUN, 3),
-            2024: date(2024, MAY, 22),
-            2025: date(2025, MAY, 11),
-        }
-        for year in visakha_bucha_year_date:
-            self.assertEqual(
-                visakha_bucha_year_date[year],
-                self.calendar.visakha_bucha_date(year),
-            )
diff --git a/tox.ini b/tox.ini
index 5773ac3c3..f1f778bcd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,42 +1,38 @@
-[pytest]
-filterwarnings =
-    # xdist/plugin.py:227
-    ignore:The --rsyncdir .* are deprecated:DeprecationWarning
+[tox]
+envlist =
+    docs
+    pre-commit
+    python3.{11, 10, 9, 8, 7}
+isolated_build = true
+skip_missing_interpreters = true
+minversion = 3.24.5
 
 [testenv]
-commands =
-    pytest
 deps =
     -r{toxinidir}/requirements/dev.txt
+commands =
+    pytest
 
 [testenv:docs]
-# Test docs.
-# We run it in Python 3.11 to match
-# https://docs.readthedocs.io/en/stable/config-file/v2.html?#build-image
-allowlist_externals =
-    cmd
-    make
-    sphinx-build
 basepython = python3.11
-commands =
-    make doc
 deps =
     -r{toxinidir}/requirements/dev.txt
     -r{toxinidir}/requirements/docs.txt
+commands =
+    make doc
+allowlist_externals =
+    cmd
+    make
+    sphinx-build
 
 [testenv:pre-commit]
 basepython = python
+deps =
+    pre-commit
 commands =
     pre-commit autoupdate
     pre-commit run --all-files
-deps =
-    pre-commit
 
-[tox]
-envlist =
-    docs
-    pre-commit
-    python3.{7,8,9,10,11}
-isoleted_build = true
-minversion = 3.24.5
-skip_missing_interpreters = true
+[pytest]
+filterwarnings =
+    ignore:The --rsyncdir .* are deprecated:DeprecationWarning