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 test_invalid_field_types(self):
        class POINT(Structure):
            pass
        self.assertRaises(TypeError, setattr, POINT, "_fields_", [("x", 1), ("y", 2)])