@abc.abstractmethod<EOL><INDENT>def unschedule_router_precommit(self, context, router_context):<DEDENT>
pass<EOL>
Perform operations specific to the routertype in preparation for
        un-scheduling of a router.

        :param context: the neutron context of the request
        :param router_context: RouterContext instance describing the current
                               state of the router, prior to the call to
                               schedule it.

        Perform operations that need to happen before un-scheduling of routers
        of this routertype. Called inside transaction context on session.
        Raising an exception will result in rollback of the transaction.