def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def test_invalid_field_types(self):
        class POINT(Structure):
            pass
        self.assertRaises(TypeError, setattr, POINT, "_fields_", [("x", 1), ("y", 2)])