def _is_list(cls, annotation: Any) -> bool:
        """Returns True if annotation is a List."""
        annotation_origin = get_origin(annotation)
        annotation_mro = getattr(annotation, "__mro__", [])
        is_list = any(x is list for x in annotation_mro)

        return (
            (annotation_origin in (list, tuple))
            or annotation_origin is abc.Sequence
            or is_list
        )
Returns True if annotation is a List.
strawberry/annotation.py