def METHOD_NAME(self):
    existing = 'a,b,c'
    model = '!q,c,d'
    expected = 'a,b,c,d'
    result = alias_utils.merge_model_and_existing_lists(model, existing)
    self.assertEqual(type(result), str, 'expected resulting list to come back as a string')
    self.assertEqual(self.__string_to_list(result), self.__string_to_list(expected))
    return