docs: def shutdown(at_time=None):
      '''
      Shutdown a running system
  
      at_time
          The wait time in minutes before the system will be shutdown.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' system.shutdown 5
      '''
      cmd = ['shutdown', '-h', ('{0}'.format(at_time) if at_time else 'now')]
      ret = __salt__['cmd.run'](cmd, python_shell=False)
      return ret