chore: add type hints and doctrings

[b8raoult]

Description

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Issue Number

Code Compatibility

• I have performed a self-review of my code

Code Performance and Testing

• I have added tests that prove my fix is effective or that my feature works
• I ran the complete Pytest test suite locally, and they pass

Dependencies

• I have ensured that the code is still pip-installable after the changes and runs
• I have tested that new dependencies themselves are pip-installable.

Documentation

• My code follows the style guidelines of this project
• I have updated the documentation and docstrings to reflect the changes
• I have added comments to my code, particularly in hard-to-understand areas

Additional Notes

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 79.16667% with 5 lines in your changes missing coverage. Please review.

Please upload report for BASE (main@4517227). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
tests/test_snow.py	20.00%	4 Missing ⚠️
tests/test_filters.py	87.50%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #45   +/-   ##
=======================================
  Coverage        ?   39.24%           
=======================================
  Files           ?        5           
  Lines           ?      158           
  Branches        ?        0           
=======================================
  Hits            ?       62           
  Misses          ?       96           
  Partials        ?        0           

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