code: def freeze_all(self):
          '''
          Stop all activity of the agents running.
          '''
          d = defer.succeed(None)
          for x in self.iter_agents():
              d.addCallback(defer.drop_param, x._cancel_long_running_protocols)
              d.addCallback(defer.drop_param, x._cancel_all_delayed_calls)
              d.addCallback(defer.drop_param, x._kill_all_protocols)
          return f freeze_all(self):
          '''
          Stop all activity of the agents running.
          '''
          d = defer.succeed(None)
          for x in self.iter_agents():
              d.addCallback(defer.drop_param, x._cancel_long_running_protocols)
              d.addCallback(defer.drop_param, x._cancel_all_delayed_calls)
              d.addCallback(defer.drop_param, x._kill_all_protocols)
          return d
docs: Stop all activity of the agents running.