code: def discard(self, element):
          
          _check_element(element)
          self._require_context()
          self._removes.add(element)
docs: Removes an element from the set.
  
          .. note: You may remove elements from the set that are not
             present, but a context from the server is required.
  
          :param element: the element to remove
          :type element: str