docs: def qtrim_back(self, name, size=1):
          """
          Sets the list element at ``index`` to ``value``. An error is returned for out of
          range indexes.
  
          :param string name: the queue name
          :param int size: the max length of removed elements        
          :return: the length of removed elements
          :rtype: int
          
          """
          size = get_positive_integer("size", size)
          return self.execute_command('qtrim_back', name, size)