Nodes do not typically know about their children or their siblings. They do know about their parents because this can be implemented pretty efficiently. As you can see, the events stream object is pretty sophisticated. Still, it has limits. You can only expand the current node because events and nodes relating to any other node are probably lost in the mists of time.
More info is here and here .
Code is here . You need Python 1.6 or at least a modern version of PyExpat to run this.