'Returns all hosts to send notification about router update'

def get_hosts_to_notify(self, context, router_id):

    hosts = super(L3_DVRsch_db_mixin, self).get_hosts_to_notify(context, router_id)
    router = self.get_router(context, router_id)
    if router.get('distributed', False):
        dvr_hosts = self._get_dvr_hosts_for_router(context, router_id)
        dvr_hosts = (set(dvr_hosts) - set(hosts))
        state = agentschedulers_db.get_admin_state_up_filter()
        agents = self.get_l3_agents(context, active=state, filters={'host': dvr_hosts})
        hosts += [a.host for a in agents]
    return hosts
