I think protocol would be appropriate here. You can define your protocol with the methods you need from Iterator

class MultiIterable(Protocol):
    def __next__(self) -> None:
        ...

    def __iter__(self) -> None:
        ...


def loop_twice(param: MultiIterable):
    for thing in param:
        print(thing)

    for thing in param:
        print(f"{thing} again")

https://typing.python.org/en/latest/spec/protocol.html#protocols