Adding nodef would be another step on the road to anarchy and nihilism. It wouldn't be long before people began using nodef as a possible value for a function, and then where would we be? Besides, using xxx = object() seems like a safer bet. Your code is unlikely to be accidentally called by someone else using your semi-private xxx object. If there were a documented official nodef object, someone would eventually call you with nodef instead of None. Terry