That's from 2015, his second complaint about interfaces vs inheritance is solved in recent versions with Protocols. Compatibility with 2.7 shouldn't be argument today either.
The complex union is as you say more a sign of a too flexible api rather than problem with type hints, the type hints just brings the root issue to the surface. I mean, why would you accept either a mapping or a list of tuples as input? Just let the user call dict(..) on the tuple-list first if they have it in such format? The documentation doesn't even mention that lists are ok for headers, only dicts: https://2.python-requests.org/en/master/api/#main-interface.
The file-tuple api with various length tuples is perhaps valid and the most convenient way to implement such options, but it's still an exceptionally unique api which requires exceptional type hints, it can be made slightly simpler which chc demonstrated above.
The complex union is as you say more a sign of a too flexible api rather than problem with type hints, the type hints just brings the root issue to the surface. I mean, why would you accept either a mapping or a list of tuples as input? Just let the user call dict(..) on the tuple-list first if they have it in such format? The documentation doesn't even mention that lists are ok for headers, only dicts: https://2.python-requests.org/en/master/api/#main-interface.
The file-tuple api with various length tuples is perhaps valid and the most convenient way to implement such options, but it's still an exceptionally unique api which requires exceptional type hints, it can be made slightly simpler which chc demonstrated above.