We decided to add this for two reasons:
- It was specifically requested by the author of the `overrides`
library, because there there are some handy runtime uses
of override information (such as propagating docstrings, which
we highlight as a concrete example)
- We realized that we actually added `__final__` to
`@typing.final` in spite of it not being specified in PEP 591,
which we felt strongly suggests that even if we omit it we
would later change our minds.
This runtime behavior is currently implemented in typing_extensions
(see https://github.com/python/typing_extensions/pull/86) as well
as pyre_extensions.
Steven Troxler
Mikko Korpela
Jelle Zijlstra
Zachary Blackwood