ruff: src public method

[SkafteNicki]

What does this PR do?

Fixes part of #1484
Add docstrings to public methods in src.

Before submitting

• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

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[codecov]

Codecov Report

Merging #1502 (db42ed6) into master (3f7e1ac) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #1502   +/-   ##
======================================
  Coverage      88%     88%           
======================================
  Files         213     213           
  Lines       10987   10987           
======================================
  Hits         9660    9660           
  Misses       1327    1327