code: def cleanup_containers(self):
          
          for cont in self.list_containers():
              if CONU_ARTIFACT_TAG in cont.name:
                  try:
                      logger.debug("removing container %s created by conu", cont)
                      # TODO: move this functionality to container.delete
                      run_cmd(["machinectl", "terminate", cont.name])
                  except subprocess.CalledProcessError as e:
                      logger.error("unable to remove container %s: %r", cont, e)
docs: stop all container created by conu
  
          :return: None