@classmethod
def filter_values(cls, part_info):
    """Filter the part_info dict list looking for instances of our class

        Args:
            part_info (dict): {part_name: [Info] or None} as returned from
                Controller.run_hook()

        Returns:
            list: [info] where info is a subclass of cls
        """
    filtered = []
    for info_list in cls.filter_parts(part_info).values():
        filtered += info_list
    return filtered
