> I typically show candidates a snippet that uses typing.Protocol as part of a broader technical discussion, and I can’t recall any candidates having seen that specific construct before

I think the `typing.Protocol` [1] (aka "structural subtyping" or "static duck typing") does not get enough spotlight! This is one of the keys to migrate a very pythonic codebase to type hints, and allows to avoid infinite type hints shenanigans all over the place. Of course, MyPy supports this feature natively [2].

[1] https://docs.python.org/3/library/typing.html [2] https://mypy.readthedocs.io/en/stable/protocols.html