def _ChangeFlags(devices, input_args, device_args_file):
  if input_args is None:
    _DisplayArgs(devices, device_args_file)
  else:
    flags = shlex.split(input_args)
    def update(device):
      flag_changer.FlagChanger(device, device_args_file).ReplaceFlags(flags)
    device_utils.DeviceUtils.parallel(devices).pMap(update)