I like black. As hprotagonist pointed out, everyone has a few things about it they don't like. What I like to do:

    $ black --skip-string-normalization my_python_script.py
    $ git add --patch my_python_script.py

Then I accept or reject all its suggestions (other than the string "normalization" idea which is not our convention) on a case-by-case basis, then `git commit; git reset HEAD --hard`.