def METHOD_NAME(self):
    existing = 'a,b,c'
    model = 'd,e,f'
    expected = 'a,b,c,d,e,f'
    result = alias_utils.merge_model_and_existing_lists(model, existing)
    self.assertEqual(type(result), str, 'expected resulting list to come back as a string')
    lists_equal, message = self.__lists_are_equal(self.__string_to_list(result), self.__string_to_list(expected))
    self.assertEqual(lists_equal, True, message)
    result = alias_utils.merge_model_and_existing_lists(model, None)
    self.assertEqual(type(result), str, 'expected resulting list to come back as a string')
    lists_equal, message = self.__lists_are_equal(self.__string_to_list(result), self.__string_to_list(model))
    self.assertEqual(lists_equal, True, message)
    result = alias_utils.merge_model_and_existing_lists(None, existing)
    self.assertEqual(type(result), str, 'expected resulting list to come back as a string')
    lists_equal, message = self.__lists_are_equal(self.__string_to_list(result), self.__string_to_list(existing))
    self.assertEqual(lists_equal, True, message)
    result = alias_utils.merge_model_and_existing_lists(None, existing.split(','))
    self.assertEqual(type(result), list, 'expected resulting list to come back as a list')
    lists_equal, message = self.__lists_are_equal(result, self.__string_to_list(existing))
    self.assertEqual(lists_equal, True, message)
    result = alias_utils.merge_model_and_existing_lists('', existing)
    self.assertEqual(type(result), str, 'expected resulting list to come back as a string')
    lists_equal, message = self.__lists_are_equal(self.__string_to_list(result), self.__string_to_list(existing))
    self.assertEqual(lists_equal, True, message)
    return