Use pre-commit [0] so people can run it client side for quick feedback, and then use whatever CI you have (Jenkins, Travis, Circle, Azure) to enforce this. The

Use pre-commit [0] so people can run it client side for quick feedback, and then use whatever CI you have (Jenkins, Travis, Circle, Azure) to enforce this. The important parts are the majority of people agree to do it, and that you have CI to be the "bad cop"/fall guy so it never becomes personal. (edit: black has pre-commit support [1], and it's easier than setting up and maintaining your own hooks IMO) [0] https://pre-commit.com/ https://pre-commit.com/ [1] https://github.com/python/black/blob/master/README.md#version-control-integration https://github.com/python/black/blob/master/README.md#versio...