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.

For some time now, Python developers have been able to “annotate” names with type information. With Python 3.5, type hints officially became part of the language (see PEP 484).

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 ...