text: """ 该代码仅为演示函数签名所用，并不能实际运行
  """
  
  train_dataset = datasets.ImageFolder(
      traindir,
      transforms.Compose([
          transforms.RandomResizedCrop(224),
          transforms.RandomHorizontalFlip(),
          transforms.ToTensor(),
          normalize,
      ]))
  train_sampler = \
      torch.utils.data.distributed.DistributedSampler(train_dataset)
  train_loader = torch.utils.data.DataLoader(
      train_dataset, batch_size=args.batch_size, 
      shuffle=(train_sampler is None),
      num_workers=args.workers, pin_memory=True, sampler=train_sampler)
  