@abc.abstractmethod<EOL><INDENT>def routes_updated(self, router_info, action, route):<DEDENT>
pass<EOL>
Routes were updated for router.

        :param router_info: RouterInfo object for this router
        :param action: Action on the route , either 'replace' or 'delete'
        :param route: route dictionary with keys 'destination' & 'next_hop'
        :returns: None