def _is_optional(cls, annotation: Any, args: list[Any]) -> bool:
        """Returns True if the annotation is Optional[SomeType]."""
        # Optionals are represented as unions
        if not cls._is_union(annotation, args):
            return False

        types = get_args(annotation)

        # A Union to be optional needs to have at least one None type
        return any(x is type(None) for x in types)
Returns True if the annotation is Optional[SomeType].
strawberry/annotation.py