def _get_internal_port(self, subnet_id):
        router_ports = self.router.get(l3_constants.INTERFACE_KEY, [])
        for port in router_ports:
            fips = port['fixed_ips']
            for f in fips:
                if f['subnet_id'] == subnet_id:
                    return port
Updates the local knowledgebase with the answer given to the question_id.
dataset/ETHPy150Open openstack/neutron/neutron/agent/l3/dvr_local_router.py/DvrLocalRouter._get_internal_port--crossover with--dataset/ETHPy150Open rouge8/20questions/webinterface.py/answer.POST