code: def refresh(self, item):
          
          client = self._clients[item].get_client()
          self[item] = val = self.item_class(client)
          return val
docs: Forces a refresh of a cached item.
  
          :param item: Client name.
          :type item: unicode | str
          :return: Items in the cache.
          :rtype: DockerHostItemCache.item_class