Actually, i only  tried this operation because its would cause a problem. the problem still continues

Blockquote
Caught TypeError in DataLoader worker process 0.
Original Traceback (most recent call last):
File “/usr/local/lib/python3.6/dist-packages/torch/utils/data/_utils/worker.py”, line 185, in _worker_loop
data = fetcher.fetch(index)
File “/usr/local/lib/python3.6/dist-packages/torch/utils/data/_utils/fetch.py”, line 44, in fetch
data = [self.dataset[idx] for idx in possibly_batched_index]
File “/usr/local/lib/python3.6/dist-packages/torch/utils/data/_utils/fetch.py”, line 44, in 
data = [self.dataset[idx] for idx in possibly_batched_index]
File “”, line 41, in getitem
sample = self.transform(sample)
File “/usr/local/lib/python3.6/dist-packages/torchvision/transforms/transforms.py”, line 61, in call
img = t(img)
File “/usr/local/lib/python3.6/dist-packages/torchvision/transforms/transforms.py”, line 172, in call
return F.to_pil_image(pic, self.mode)
File “/usr/local/lib/python3.6/dist-packages/torchvision/transforms/functional.py”, line 190, in to_pil_image
raise TypeError(‘pic should be Tensor or ndarray. Got {}.’.format(type(pic)))
TypeError: pic should be Tensor or ndarray. Got <class ‘dict’>.