def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def block_size_filter(entity):
        return (
            entity.size[0] * 2 >= entity.size[1] * 2
            and entity.size[1] <= 16
            and entity.size[3] <= 4
        )