The first line of python docstrings is meant to always end with a period: PEP 257
As I only learned of this recently I tried to fix it in my existing code. Tools like ruff can do that partially for function and class docstrings, but I also regularly use attribute docstrings.
Therefore I used a vim regex:
:%s/^\(\s*\)"""\(\(\s*[^."]\+\)\+\)\("""\)\?\s*$/\1"""\2.\4/g