def METHOD_NAME(self, faker, keys, values):
    with patch(
        "tavern._core.pytest.file.get_wrapped_create_function",
        lambda _: lambda: values,
    ):
        marks = [
            {"parametrize": {"key": keys, "vals": {"$ext": {"function": "a:v"}}}}
        ]
        with pytest.raises(exceptions.BadSchemaError):
            get_parametrised_tests(marks)