Message 303839 - Python tracker
You can use Iterator type, for example this works in mypy (didn't test in other type checkers):
def f() -> Iterator[int]:
yield 42
In case you want annotate something specifically as Generator[int, None, None] (for example to use its .close() method), then you can create a generic alias:
T = TypeVar('T')
Gen = Generator[T, None, None]
def f() -> Gen[int]:
...
this is supported by mypy as well.