Consider adding wemake-python-styleguide

[sobolevn]

wemake-python-styleguide is the strictest python linter.
Inside it is just a flake8 plugin, which you already use.

Repo: https://github.com/wemake-services/wemake-python-styleguide
Docs: https://wemake-python-stylegui.de/en/latest/