| ▲ | nephanth 3 days ago | |
You are slightly wrong. Python does allow you to put anything in annotations. ( pep 3107 that defines type annotations says that explicitly [1]). But it also defines a type checking annotations, which is a specific convention for using pep 3107 annotations. Type annotations were introduced in PEP 484 and updated in a lot of subsequent peps. The python typing system is fully specified in [3]. It does have several implementations, although the reference implementation is mypy [1]: https://peps.python.org/pep-3107/#rejected-proposals | ||