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_base_class_pre_update_validate_raises_error(self):
        with self.assertRaisesRegex(
            NotImplementedError,
            'Subclasses of BaseSuggestion should implement'
            ' pre_update_validate.'):
            self.base_suggestion.pre_update_validate({})