@abc.abstractmethod<EOL><INDENT>def register_for_changed_agency(self, agency_id):<DEDENT>
pass<EOL>
Registers for notification of an updated agency.

        ``AgencyReceiver.changedAgencies()`` is invoked when the
        specified agency is changed.

        :param agency_id: the ``Id`` of the agency to monitor
        :type agency_id: ``osid.id.Id``
        :raise: ``NullArgument`` -- ``agency_id`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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