As someone who has written some Python at work, whenever I need to work on some code without type hints, I spend way too much time trying to figure out what all the parameter types should be for functions. I can’t be the only one doing this though, I’ve seen functions that assume their inputs are strings receiving pathlib.Path on some uncommon branch that sure enough errors on some obscure user inputs.

I’ve been pushing mypy hard though. It’s not perfect, but it works well enough that it’s still worth using over not using. The biggest pushback has actually been from the amount of time we’d have to spend fixing type-related bugs instead of developing new features.