def METHOD_NAME(self, *keys: str) -> Callable[[FILTER_ARGS], Optional[str]]:
    def validator(d: FILTER_ARGS) -> Optional[str]:
        for k in keys:
            if k in d:  # type: ignore[operator]  # We assume FILTER_ARGS is a dict
                return None
        return f"Filter must contain at least one of: {keys}"
    return validator