def _handle_remove(self, del_id): 
		'''
		Called on delete. Updates the candidate by predecessor dict.

		:param del_id: (int) id of deleted candidate
		:rtype: None
		'''

		with self.lock:
			candidate = self.candidate_by_predecessor.get(del_id, None)
			if del_id == None:
				get_logger().warning(
					"LeaderQueue._handle_remove Unknown candidate %s" %
					(del_id))
			elif candidate == None: 
				get_logger().debug(
					"LeaderQueue._handle_remove Removed candidate is not"
					+ " a predecessor %s" % (del_id))
			else:
				self._update_predecessor_dict(del_id, candidate)
				del self.candidate_by_predecessor[del_id]
		return None
dataset/ETHPy150Open Knewton/pettingzoo-python/pettingzoo/leader_queue.py/LeaderQueue._handle_remove/original