mypy and next.py

class One:
    def __next__(self) -> int:
        return 1

class OneStr:
    def __init__(self) -> None:
        self.iterable = One()

    def __next__(self) -> str:
        return str(next(self.iterable))
        
# mypy foo.py 
# foo.py: note: In member "__next__" of class "OneStr":
# foo.py:10: error: No overload variant of "next" matches argument types [foo.One]