diff --git a/containers/teuthology-dev/teuthology.sh b/containers/teuthology-dev/teuthology.sh
index b7c3922f4..373f6efb8 100755
--- a/containers/teuthology-dev/teuthology.sh
+++ b/containers/teuthology-dev/teuthology.sh
@@ -28,6 +28,7 @@ if [ "$TEUTHOLOGY_SUITE" != "none" ]; then
         --filter-out "libcephfs,kclient" \
         --force-priority \
         --seed 349 \
+        ${TEUTHOLOGY_SUITE_EXTRA_ARGS} \
         $TEUTHOLOGY_CONF
     DISPATCHER_EXIT_FLAG='--exit-on-empty-queue'
     teuthology-queue -m $TEUTHOLOGY_MACHINE_TYPE -s | \
diff --git a/docs/siteconfig.rst b/docs/siteconfig.rst
index 96d2658c4..effb8219c 100644
--- a/docs/siteconfig.rst
+++ b/docs/siteconfig.rst
@@ -81,12 +81,16 @@ Here is a sample configuration with many of the options set and documented::
     # itself from git. This is disabled by default.
     automated_scheduling: false
 
-    # How often, in seconds, teuthology-worker should poll its child job 
+    # How often, in seconds, teuthology-supervisor should poll its child job
     # processes
     watchdog_interval: 120
 
+    # How old a scheduled job can be, in seconds, before the dispatcher
+    # considers it 'expired', skipping it.
+    max_job_age: 1209600
+
     # How long a scheduled job should be allowed to run, in seconds, before 
-    # it is killed by the worker process.
+    # it is killed by the supervisor process.
     max_job_time: 259200
 
     # The template from which the URL of the repository containing packages
diff --git a/scripts/suite.py b/scripts/suite.py
index 77561b7e0..c98a5cb89 100644
--- a/scripts/suite.py
+++ b/scripts/suite.py
@@ -112,6 +112,10 @@
                               When tests finish or time out, send an email
                               here. May also be specified in ~/.teuthology.yaml
                               as 'results_email'
+  --expire <datetime>         Do not execute jobs in the run if they have not
+                              completed by this time. Valid formats include
+                              ISO 8601, and relative offsets like '90s', '30m',
+                              '1h', '3d', or '1w'
   --rocketchat <rocketchat>   Comma separated list of Rocket.Chat channels where
                               to send a message when tests finished or time out.
                               To be used with --sleep-before-teardown option.
diff --git a/teuthology/config.py b/teuthology/config.py
index 3983d3d0f..30204aa46 100644
--- a/teuthology/config.py
+++ b/teuthology/config.py
@@ -33,12 +33,13 @@ def __init__(self, yaml_path=None):
             self._conf = dict()
 
     def load(self, conf=None):
-        if conf:
+        if conf is not None:
             if isinstance(conf, dict):
                 self._conf = conf
-            else:
+                return
+            elif conf:
                 self._conf = yaml.safe_load(conf)
-            return
+                return
         if os.path.exists(self.yaml_path):
             with open(self.yaml_path) as f:
                 self._conf = yaml.safe_load(f)
@@ -157,6 +158,7 @@ class TeuthologyConfig(YamlConfig):
         'job_threshold': 500,
         'lab_domain': 'front.sepia.ceph.com',
         'lock_server': 'http://paddles.front.sepia.ceph.com/',
+        'max_job_age': 1209600,  # 2 weeks
         'max_job_time': 259200,  # 3 days
         'nsupdate_url': 'http://nsupdate.front.sepia.ceph.com/update',
         'results_server': 'http://paddles.front.sepia.ceph.com/',
diff --git a/teuthology/dispatcher/__init__.py b/teuthology/dispatcher/__init__.py
index 15c4003c9..59f8ae327 100644
--- a/teuthology/dispatcher/__init__.py
+++ b/teuthology/dispatcher/__init__.py
@@ -22,6 +22,7 @@
 from teuthology.dispatcher import supervisor
 from teuthology.exceptions import BranchNotFoundError, CommitNotFoundError, SkipJob, MaxWhileTries
 from teuthology.lock import ops as lock_ops
+from teuthology.util.time import parse_timestamp
 from teuthology import safepath
 
 log = logging.getLogger(__name__)
@@ -234,6 +235,8 @@ def match(proc):
 
 def prep_job(job_config, log_file_path, archive_dir):
     job_id = job_config['job_id']
+    check_job_expiration(job_config)
+
     safe_archive = safepath.munge(job_config['name'])
     job_config['worker_log'] = log_file_path
     archive_path_full = os.path.join(
@@ -308,6 +311,31 @@ def prep_job(job_config, log_file_path, archive_dir):
     return job_config, teuth_bin_path
 
 
+def check_job_expiration(job_config):
+    job_id = job_config['job_id']
+    expired = False
+    now = datetime.datetime.now(datetime.timezone.utc)
+    if expire_str := job_config.get('timestamp'):
+        expire = parse_timestamp(expire_str) + \
+            datetime.timedelta(seconds=teuth_config.max_job_age)
+        expired = expire < now
+    if not expired and (expire_str := job_config.get('expire')):
+        try:
+            expire = parse_timestamp(expire_str)
+            expired = expired or expire < now
+        except ValueError:
+            log.warning(f"Failed to parse job expiration: {expire_str=}")
+            pass
+    if expired:
+        log.info(f"Skipping job {job_id} because it is expired: {expire_str} is in the past")
+        report.try_push_job_info(
+            job_config,
+            # TODO: Add a 'canceled' status to paddles, and use that.
+            dict(status='dead'),
+        )
+        raise SkipJob()
+
+
 def lock_machines(job_config):
     report.try_push_job_info(job_config, dict(status='running'))
     fake_ctx = supervisor.create_fake_context(job_config, block=True)
diff --git a/teuthology/dispatcher/supervisor.py b/teuthology/dispatcher/supervisor.py
index d2e86de36..83e6d997c 100644
--- a/teuthology/dispatcher/supervisor.py
+++ b/teuthology/dispatcher/supervisor.py
@@ -8,7 +8,7 @@
 
 from urllib.parse import urljoin
 
-from teuthology import exporter, kill, report, safepath
+from teuthology import exporter, dispatcher, kill, report, safepath
 from teuthology.config import config as teuth_config
 from teuthology.exceptions import SkipJob, MaxWhileTries
 from teuthology import setup_log_file, install_except_hook
@@ -37,6 +37,10 @@ def main(args):
                                  f"supervisor.{job_config['job_id']}.log")
     setup_log_file(log_file_path)
     install_except_hook()
+    try:
+        dispatcher.check_job_expiration(job_config)
+    except SkipJob:
+        return 0
 
     # reimage target machines before running the job
     if 'targets' in job_config:
@@ -54,25 +58,22 @@ def main(args):
         with open(args.job_config, 'w') as f:
             yaml.safe_dump(job_config, f, default_flow_style=False)
 
-    try:
-        suite = job_config.get("suite")
-        if suite:
-            with exporter.JobTime().time(suite=suite):
-                return run_job(
-                    job_config,
-                    args.bin_path,
-                    args.archive_dir,
-                    args.verbose
-                )
-        else:
+    suite = job_config.get("suite")
+    if suite:
+        with exporter.JobTime().time(suite=suite):
             return run_job(
                 job_config,
                 args.bin_path,
                 args.archive_dir,
                 args.verbose
             )
-    except SkipJob:
-        return 0
+    else:
+        return run_job(
+            job_config,
+            args.bin_path,
+            args.archive_dir,
+            args.verbose
+        )
 
 
 def run_job(job_config, teuth_bin_path, archive_dir, verbose):
diff --git a/teuthology/dispatcher/test/test_dispatcher.py b/teuthology/dispatcher/test/test_dispatcher.py
index e7c59d8bd..58f58cf9c 100644
--- a/teuthology/dispatcher/test/test_dispatcher.py
+++ b/teuthology/dispatcher/test/test_dispatcher.py
@@ -7,6 +7,7 @@
 from teuthology import dispatcher
 from teuthology.config import FakeNamespace
 from teuthology.contextutil import MaxWhileTries
+from teuthology.util.time import TIMESTAMP_FMT
 
 
 class TestDispatcher(object):
@@ -172,3 +173,31 @@ def test_main_loop_13925(
         for i in range(len(jobs)):
             push_call = m_try_push_job_info.call_args_list[i]
             assert push_call[0][1]['status'] == 'dead'
+
+    @pytest.mark.parametrize(
+        ["timestamp", "expire", "skip"],
+        [
+            [datetime.timedelta(days=-1), None, False],
+            [datetime.timedelta(days=-30), None, True],
+            [None, datetime.timedelta(days=1), False],
+            [None, datetime.timedelta(days=-1), True],
+            [datetime.timedelta(days=-1), datetime.timedelta(days=1), False],
+            [datetime.timedelta(days=1), datetime.timedelta(days=-1), True],
+        ]
+    )
+    @patch("teuthology.dispatcher.report.try_push_job_info")
+    def test_check_job_expiration(self, _, timestamp, expire, skip):
+        now = datetime.datetime.now(datetime.timezone.utc)
+        job_config = dict(
+            job_id="1",
+            name="job_name",
+        )
+        if timestamp:
+            job_config["timestamp"] = (now + timestamp).strftime(TIMESTAMP_FMT)
+        if expire:
+            job_config["expire"] = (now + expire).strftime(TIMESTAMP_FMT)
+        if skip:
+            with pytest.raises(dispatcher.SkipJob):
+                dispatcher.check_job_expiration(job_config)
+        else:
+            dispatcher.check_job_expiration(job_config)
diff --git a/teuthology/suite/__init__.py b/teuthology/suite/__init__.py
index 6fc167fab..8a17cf5f1 100644
--- a/teuthology/suite/__init__.py
+++ b/teuthology/suite/__init__.py
@@ -63,6 +63,9 @@ def process_args(args):
         elif key == 'subset' and value is not None:
             # take input string '2/3' and turn into (2, 3)
             value = tuple(map(int, value.split('/')))
+        elif key == 'expire' and value is None:
+            # Skip empty 'expire' values
+            continue
         elif key in ('filter_all', 'filter_in', 'filter_out', 'rerun_statuses'):
             if not value:
                 value = []
diff --git a/teuthology/suite/placeholder.py b/teuthology/suite/placeholder.py
index 3a1775117..f812fccac 100644
--- a/teuthology/suite/placeholder.py
+++ b/teuthology/suite/placeholder.py
@@ -45,6 +45,7 @@ def _substitute(input_dict, values_dict):
 # Template for the config that becomes the base for each generated job config
 dict_templ = {
     'branch': Placeholder('ceph_branch'),
+    'expire': Placeholder('expire'),
     'sha1': Placeholder('ceph_hash'),
     'teuthology_branch': Placeholder('teuthology_branch'),
     'teuthology_sha1': Placeholder('teuthology_sha1'),
diff --git a/teuthology/suite/run.py b/teuthology/suite/run.py
index 8fa45b5b4..4f425cada 100644
--- a/teuthology/suite/run.py
+++ b/teuthology/suite/run.py
@@ -1,4 +1,5 @@
 import copy
+import datetime
 import logging
 import os
 import pwd
@@ -8,7 +9,6 @@
 
 from humanfriendly import format_timespan
 
-from datetime import datetime
 from tempfile import NamedTemporaryFile
 from teuthology import repo_utils
 
@@ -24,6 +24,7 @@
 from teuthology.suite.merge import config_merge
 from teuthology.suite.build_matrix import build_matrix
 from teuthology.suite.placeholder import substitute_placeholders, dict_templ
+from teuthology.util.time import parse_offset, parse_timestamp, TIMESTAMP_FMT
 
 log = logging.getLogger(__name__)
 
@@ -43,7 +44,7 @@ def __init__(self, args):
         self.args = args
         # We assume timestamp is a datetime.datetime object
         self.timestamp = self.args.timestamp or \
-            datetime.now().strftime('%Y-%m-%d_%H:%M:%S')
+            datetime.datetime.now().strftime(TIMESTAMP_FMT)
         self.user = self.args.user or pwd.getpwuid(os.getuid()).pw_name
 
         self.name = self.make_run_name()
@@ -86,6 +87,15 @@ def create_initial_config(self):
 
         :returns: A JobConfig object
         """
+        now = datetime.datetime.now(datetime.timezone.utc)
+        expires = self.get_expiration()
+        if expires:
+            if now > expires:
+                util.schedule_fail(
+                    f"Refusing to schedule because the expiration date is in the past: {self.args.expire}",
+                    dry_run=self.args.dry_run,
+                )
+
         self.os = self.choose_os()
         self.kernel_dict = self.choose_kernel()
         ceph_hash = self.choose_ceph_hash()
@@ -122,9 +132,29 @@ def create_initial_config(self):
             suite_repo=config.get_ceph_qa_suite_git_url(),
             suite_relpath=self.args.suite_relpath,
             flavor=self.args.flavor,
+            expire=expires.strftime(TIMESTAMP_FMT) if expires else None,
         )
         return self.build_base_config()
 
+    def get_expiration(self, _base_time: datetime.datetime | None = None) -> datetime.datetime | None:
+        """
+        _base_time: For testing, calculate relative offsets from this base time
+
+        :returns:   True if the job should run; False if it has expired
+        """
+        log.info(f"Checking for expiration ({self.args.expire})")
+        expires_str = self.args.expire
+        if expires_str is None:
+            return None
+        now = datetime.datetime.now(datetime.timezone.utc)
+        if _base_time is None:
+            _base_time = now
+        try:
+            expires = parse_timestamp(expires_str)
+        except ValueError:
+            expires = _base_time + parse_offset(expires_str)
+        return expires
+
     def choose_os(self):
         os_type = self.args.distro
         os_version = self.args.distro_version
diff --git a/teuthology/suite/test/conftest.py b/teuthology/suite/test/conftest.py
new file mode 100644
index 000000000..4285bdcfc
--- /dev/null
+++ b/teuthology/suite/test/conftest.py
@@ -0,0 +1,4 @@
+from teuthology.config import config
+
+def pytest_runtest_setup():
+    config.load({})
diff --git a/teuthology/suite/test/test_placeholder.py b/teuthology/suite/test/test_placeholder.py
index acf1b6a44..31b51755d 100644
--- a/teuthology/suite/test/test_placeholder.py
+++ b/teuthology/suite/test/test_placeholder.py
@@ -22,7 +22,8 @@ def test_substitute_placeholders(self):
             suite_repo='https://example.com/ceph/suite.git',
             suite_relpath='',
             ceph_repo='https://example.com/ceph/ceph.git',
-            flavor='default'
+            flavor='default',
+            expire='expire',
         )
         output_dict = substitute_placeholders(dict_templ, input_dict)
         assert output_dict['suite'] == 'suite'
@@ -50,6 +51,7 @@ def test_null_placeholders_dropped(self):
             suite_relpath='',
             ceph_repo='https://example.com/ceph/ceph.git',
             flavor=None,
+            expire='expire',
         )
         output_dict = substitute_placeholders(dict_templ, input_dict)
         assert 'os_type' not in output_dict
diff --git a/teuthology/suite/test/test_run_.py b/teuthology/suite/test/test_run_.py
index 1dc23e20d..51ce29a85 100644
--- a/teuthology/suite/test/test_run_.py
+++ b/teuthology/suite/test/test_run_.py
@@ -4,7 +4,7 @@
 import contextlib
 import yaml
 
-from datetime import datetime
+from datetime import datetime, timedelta, timezone
 from mock import patch, call, ANY
 from io import StringIO
 from io import BytesIO
@@ -12,6 +12,7 @@
 from teuthology.config import config, YamlConfig
 from teuthology.exceptions import ScheduleFailError
 from teuthology.suite import run
+from teuthology.util.time import TIMESTAMP_FMT
 
 
 class TestRun(object):
@@ -52,7 +53,7 @@ def test_email_addr(self, m_git_validate_sha1, m_choose_ceph_version,
 
     @patch('teuthology.suite.run.util.fetch_repos')
     def test_name(self, m_fetch_repos):
-        stamp = datetime.now().strftime('%Y-%m-%d_%H:%M:%S')
+        stamp = datetime.now().strftime(TIMESTAMP_FMT)
         with patch.object(run.Run, 'create_initial_config',
                           return_value=run.JobConfig()):
             name = run.Run(self.args).name
@@ -89,6 +90,45 @@ def test_branch_nonexistent(
         with pytest.raises(ScheduleFailError):
             self.klass(self.args)
 
+    @pytest.mark.parametrize(
+        ["expire", "delta", "result"],
+        [
+            [None, timedelta(), False],
+            ["1m", timedelta(), True],
+            ["1m", timedelta(minutes=-2), False],
+            ["1m", timedelta(minutes=2), True],
+            ["7d", timedelta(days=-14), False],
+        ]
+    )
+    @patch('teuthology.repo_utils.fetch_repo')
+    @patch('teuthology.suite.run.util.git_branch_exists')
+    @patch('teuthology.suite.run.util.package_version_for_hash')
+    @patch('teuthology.suite.run.util.git_ls_remote')
+    def test_get_expiration(
+        self,
+        m_git_ls_remote,
+        m_package_version_for_hash,
+        m_git_branch_exists,
+        m_fetch_repo,
+        expire,
+        delta,
+        result,
+    ):
+        m_git_ls_remote.side_effect = 'hash'
+        m_package_version_for_hash.return_value = 'a_version'
+        m_git_branch_exists.return_value = True
+        self.args.expire = expire
+        obj = self.klass(self.args)
+        now = datetime.now(timezone.utc)
+        expires_result = obj.get_expiration(_base_time=now + delta)
+        if expire is None:
+            assert expires_result is None
+            assert obj.base_config['expire'] is None
+        else:
+            assert expires_result is not None
+            assert (now < expires_result) is result
+            assert obj.base_config['expire']
+
     @patch('teuthology.suite.run.util.fetch_repos')
     @patch('requests.head')
     @patch('teuthology.suite.run.util.git_branch_exists')
diff --git a/teuthology/test/test_misc.py b/teuthology/test/test_misc.py
index 22341239c..f2a6ebfb8 100644
--- a/teuthology/test/test_misc.py
+++ b/teuthology/test/test_misc.py
@@ -1,12 +1,13 @@
 import argparse
+import pytest
+import subprocess
 
 from unittest.mock import Mock, patch
-from teuthology.orchestra import cluster
-from teuthology.config import config
-from teuthology import misc
-import subprocess
 
-import pytest
+from teuthology import misc
+from teuthology.config import config
+from teuthology.orchestra import cluster
+from teuthology.orchestra.remote import Remote
 
 
 class FakeRemote(object):
@@ -26,7 +27,7 @@ def test_sh_truncate(caplog):
 
 def test_sh_fail(caplog):
     with pytest.raises(subprocess.CalledProcessError) as excinfo:
-        misc.sh("/bin/echo -n AB ; /bin/echo C ; exit 111", 2) == "ABC\n"
+        misc.sh("/bin/echo -n AB ; /bin/echo C ; exit 111", 2)
     assert excinfo.value.returncode == 111
     for record in caplog.records:
         if record.levelname == 'ERROR':
@@ -34,29 +35,20 @@ def test_sh_fail(caplog):
                     'ABC\n' == record.message)
 
 def test_sh_progress(caplog):
-    misc.sh("echo AB ; sleep 5 ; /bin/echo C", 2) == "ABC\n"
+    assert misc.sh("echo AB ; sleep 0.1 ; /bin/echo C", 2) == "AB\nC\n"
     records = caplog.records
     assert ':sh: ' in records[0].message
     assert 'AB' == records[1].message
     assert 'C' == records[2].message
-    #
-    # With a sleep 5 between the first and the second message,
-    # there must be at least 2 seconds between the log record
-    # of the first message and the log record of the second one
-    #
-    assert (records[2].created - records[1].created) > 2
+    assert records[2].created > records[1].created
 
 
 def test_wait_until_osds_up():
     ctx = argparse.Namespace()
     ctx.daemons = Mock()
     ctx.daemons.iter_daemons_of_role.return_value = list()
-    remote = FakeRemote()
-
-    def s(self, **kwargs):
-        return 'IGNORED\n{"osds":[{"state":["up"]}]}'
-
-    remote.sh = s
+    remote = Mock(spec=Remote)
+    remote.sh.return_value = 'IGNORED\n{"osds":[{"state":["up"]}]}'
     ctx.cluster = cluster.Cluster(
         remotes=[
             (remote, ['osd.0', 'client.1'])
@@ -64,7 +56,7 @@ def s(self, **kwargs):
     )
     with patch.multiple(
             misc,
-            get_testdir=lambda ctx: "TESTDIR",
+            get_testdir=lambda _: "TESTDIR",
     ):
         misc.wait_until_osds_up(ctx, ctx.cluster, remote)
 
diff --git a/teuthology/util/test/test_time.py b/teuthology/util/test/test_time.py
new file mode 100644
index 000000000..c37b5f2f5
--- /dev/null
+++ b/teuthology/util/test/test_time.py
@@ -0,0 +1,54 @@
+import pytest
+
+from datetime import datetime, timedelta, timezone
+from typing import Type
+
+from teuthology.util import time
+
+
+@pytest.mark.parametrize(
+    ["timestamp", "result"],
+    [
+        ["1999-12-31_23:59:59", datetime(1999, 12, 31, 23, 59, 59, tzinfo=timezone.utc)],
+        ["1999-12-31_23:59", datetime(1999, 12, 31, 23, 59, 0, tzinfo=timezone.utc)],
+        ["1999-12-31T23:59:59", datetime(1999, 12, 31, 23, 59, 59, tzinfo=timezone.utc)],
+        ["1999-12-31T23:59:59+00:00", datetime(1999, 12, 31, 23, 59, 59, tzinfo=timezone.utc)],
+        ["1999-12-31T17:59:59-06:00", datetime(1999, 12, 31, 23, 59, 59, tzinfo=timezone.utc)],
+        ["2024-01-01", datetime(2024, 1, 1, 0, 0, tzinfo=timezone.utc)],
+        ["tomorrow", ValueError],
+        ["1d", ValueError],
+        ["", ValueError],
+        ["2024", ValueError],
+
+    ]
+)
+def test_parse_timestamp(timestamp: str, result: datetime | Type[Exception]):
+    if isinstance(result, datetime):
+        assert time.parse_timestamp(timestamp) == result
+    else:
+        with pytest.raises(result):
+            time.parse_timestamp(timestamp)
+
+
+@pytest.mark.parametrize(
+    ["offset", "result"],
+    [
+        ["1s", timedelta(seconds=1)],
+        ["1m", timedelta(minutes=1)],
+        ["1h", timedelta(hours=1)],
+        ["1d", timedelta(days=1)],
+        ["1w", timedelta(weeks=1)],
+        ["365d", timedelta(days=365)],
+        ["1x", ValueError],
+        ["-1m", ValueError],
+        ["0xde", ValueError],
+        ["frog", ValueError],
+        ["7dwarfs", ValueError],
+    ]
+)
+def test_parse_offset(offset: str, result: timedelta | Type[Exception]):
+    if isinstance(result, timedelta):
+        assert time.parse_offset(offset) == result
+    else:
+        with pytest.raises(result):
+            time.parse_offset(offset)
diff --git a/teuthology/util/time.py b/teuthology/util/time.py
new file mode 100644
index 000000000..8e0525fcc
--- /dev/null
+++ b/teuthology/util/time.py
@@ -0,0 +1,52 @@
+import re
+
+from datetime import datetime, timedelta, timezone
+
+# When we're not using ISO format, we're using this
+TIMESTAMP_FMT = "%Y-%m-%d_%H:%M:%S"
+
+def parse_timestamp(timestamp: str) -> datetime:
+    """
+    timestamp: A string either in ISO 8601 format or TIMESTAMP_FMT.
+               If no timezone is specified, UTC is assumed.
+
+    :returns: a datetime object
+    """
+    try:
+        dt = datetime.fromisoformat(timestamp)
+    except ValueError:
+        dt = datetime.strptime(timestamp, TIMESTAMP_FMT)
+    if dt.tzinfo is None:
+        dt = dt.replace(tzinfo=timezone.utc)
+    return dt
+
+def parse_offset(offset: str) -> timedelta:
+    """
+    offset: A string consisting of digits followed by one of the following
+            characters:
+                s: seconds
+                m: minutes
+                h: hours
+                d: days
+                w: weeks
+    """
+    err_msg = "Offsets must either be an ISO 8601-formatted timestamp or " \
+        f"a relative value like '2w', '1d', '7h', '45m', '90s'. Got: {offset}"
+    match = re.match(r'(\d+)(s|m|h|d|w)$', offset)
+    if match is None:
+        raise ValueError(err_msg)
+    num = int(match.groups()[0])
+    unit = match.groups()[1]
+    match unit:
+        case 's':
+            return timedelta(seconds=num)
+        case 'm':
+            return timedelta(minutes=num)
+        case 'h':
+            return timedelta(hours=num)
+        case 'd':
+            return timedelta(days=num)
+        case 'w':
+            return timedelta(weeks=num)
+        case _:
+            raise ValueError(err_msg)