def METHOD_NAME(self):
    """ Add or remove user notifiers for the objects observed by the root
    observer.
    """
    if not self.graph.node.notify:
        return
    for observable in self.graph.node.iter_observables(self.object):
        notifier = self.graph.node.get_notifier(
            handler=self.handler,
            target=self.target,
            dispatcher=self.dispatcher,
        )
        if self.remove:
            notifier.remove_from(observable)
        else:
            notifier.add_to(observable)
        self._processed.append((notifier, observable))