Type annotations aren’t equivalent to this check, though, because they’re not enforced at runtime.
They can (as in - there's API for that, the rest is up to a community effort) improve performance of a final program, if type-annotated code is passed through Cython with ``annotation_typing=True`` flag:
http://docs.cython.org/en/latest/src/tutorial/pure.html#stat...
https://github.com/cython/cython/issues/1672#issuecomment-29...