Mypy, Pytype, Pyright, and Pyre can help you keep your type-hinted Python code bug-free. Let’s see what each of these useful tools has to offer.

If you need an explicit self hint for the class that refers to whatever class is in context, and you’re using Python 3.11 or later, you can import Self from the typing module and use that as a hint.

I've grabbed Sequence from the typing module, which includes all three Python sequence types—strings, lists and tuples. Once I do that, all of the mypy problems disappear, because all of the arguments ...

But function isn't actually a recognized name in Python. Instead, you'll need to use the typing module, which comes with Python 3 so you can do this kind of type checking. And in typing, the name ...