@abc.abstractmethod<EOL><INDENT>def register_for_deleted_agents(self):<DEDENT>
pass<EOL>
Registers for notification of deleted agents.

        ``AgentReceiver.deletedAgents()`` is invoked when an agent is
        removed from this agency.

        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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