def METHOD_NAME(
    group_type: PropertyType, left_values: List[str], right_values: List[str]
) -> Optional[float]:
    if not left_values and not right_values:
        raise ValueError("At least one proxy must have property type: %s", group_type)
    elif not left_values or not right_values:
        return None
    return group_type.compare_sets(left_values, right_values)