'Get IDs of routers that the agent should host
Overridden for DVR to handle agents in \'dvr\' mode which have
no explicit bindings with routers'

def _get_router_ids_for_agent(self, context, agent, router_ids):

    filters = {'l3_agent_id': agent.id}
    if router_ids:
        filters['router_id'] = router_ids
    bindings = rb_obj.RouterL3AgentBinding.get_objects(context, **filters)
    return [item.router_id for item in bindings]
