container.py 文件源码

def enumerate(self, item: Any, reverse: bool = False) -> Generator[Tuple[int, Any], None, None]:
        items = self
        if reverse:
            max = len(items) - 1
            items = reversed(items)
        for index, x in enumerate(items):
            if x == item:
                yield max - index if reverse else index, x
                continue

            try:
                if item in x:
                    yield max - index if reverse else index, x
            except TypeError:
                # x doesn't define __contains__
                pass