code: def delete_intf_router(self, name, tenant_id, rout_id, subnet_lst):
          
          try:
              for subnet_id in subnet_lst:
                  body = {'subnet_id': subnet_id}
                  intf = self.neutronclient.remove_interface_router(rout_id,
                                                                    body=body)
                  intf.get('id')
          except Exception as exc:
              LOG.error("Failed to delete router interface %(name)s, "
                        " Exc %(exc)s", {'name': name, 'exc': str(exc)})
              return False
          return True
docs: Delete the openstack router and remove the interfaces attached.