docs: def add_to_item_list_by_name(self, item_urls, item_list_name):
          """ Instruct the server to add the given items to the specified
          Item List (which will be created if it does not already exist)
  
          :type item_urls: List or ItemGroup
          :param item_urls: List of URLs for the items to add,
              or an ItemGroup object
          :type item_list_name: String
          :param item_list_name: name of the item list to retrieve
  
          :rtype: String
          :returns: the server success message, if successful
  
          :raises: APIError if the request was not successful
  
  
          """
          url_name = urlencode((('name', item_list_name),))
          request_url = '/item_lists?' + url_name
  
          data = json.dumps({'items': list(item_urls)})
          resp = self.api_request(request_url,  method='POST', data=data)
          return self.__check_success(resp)