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_execute(self):
        opt = Optional(None, execute=dict)
        self.assertEqual(deoption(opt), {})
        self.assertEqual(deoption(opt, execute=dict), {})
        self.assertEqual(deoption(None, execute=dict), {})