code: def add(self, item):
          
          def result_fnc(f):
              if f.result():
                  return True
              raise Full("Queue is full!")
  
          return self.offer(item).continue_with(result_fnc)
docs: Adds the specified item to this queue if there is available space.
  
          :param item: (object), the specified item.
          :return: (bool), ``true`` if element is successfully added, ``false`` otherwise.