code: def _delete_dummy_intf_rtr(self, tenant_id, tenant_name, rtr_id):
          
          dummy_router_dict = self.get_dummy_router_net(tenant_id)
          ret = self.delete_os_dummy_rtr_nwk(dummy_router_dict.get('router_id'),
                                             dummy_router_dict.get('net_id'),
                                             dummy_router_dict.get('subnet_id'))
          # Release the network DB entry
          self.delete_network_db(dummy_router_dict.get('net_id'))
          return ret
docs: Function to delete a dummy interface of a router.