code: def get_router_id(self, tenant_id, tenant_name):
          
          router_id = None
          if tenant_id in self.tenant_dict:
              router_id = self.tenant_dict.get(tenant_id).get('router_id')
          if not router_id:
              router_list = self.os_helper.get_rtr_by_name(
                  'FW_RTR_' + tenant_name)
              if len(router_list) > 0:
                  router_id = router_list[0].get('id')
          return router_id
docs: Retrieve the router ID.