@abc.abstractmethod<EOL><INDENT>def changed_child_of_catalogs(self, notification_id, catalog_ids):<DEDENT>
pass<EOL>
The callback for notifications of changes to children of catalog hierarchy nodes.

        :param notification_id: the notification ``Id``
        :type notification_id: ``osid.id.Id``
        :param catalog_ids: the ``Ids`` of the ``Catalogs`` whose children have changed
        :type catalog_ids: ``osid.id.IdList``


        *compliance: mandatory -- This method must be implemented.*