_pickle.UnpicklingError: A load persistent id instruction was encountered, but no persistent_load function was specified.

[passingdragon]

Traceback (most recent call last):
File "main_train_dncnn_denoising_b.py", line 250, in
main()
File "main_train_dncnn_denoising_b.py", line 154, in main
for i, train_data in enumerate(train_loader):
File "/DATA/zcl/myConda/miniconda/envs/BBCU/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 628, in next
data = self._next_data()
File "/DATA/zcl/myConda/miniconda/envs/BBCU/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 1333, in _next_data
return self._process_data(data)
File "/DATA/zcl/myConda/miniconda/envs/BBCU/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 1359, in _process_data
data.reraise()
File "/DATA/zcl/myConda/miniconda/envs/BBCU/lib/python3.8/site-packages/torch/_utils.py", line 543, in reraise
raise exception
_pickle.UnpicklingError: Caught UnpicklingError in DataLoader worker process 0.
Original Traceback (most recent call last):
File "/DATA/zcl/myConda/miniconda/envs/BBCU/lib/python3.8/site-packages/torch/utils/data/_utils/worker.py", line 302, in _worker_loop
data = fetcher.fetch(index)
File "/DATA/zcl/myConda/miniconda/envs/BBCU/lib/python3.8/site-packages/torch/utils/data/_utils/fetch.py", line 58, in fetch
data = [self.dataset[idx] for idx in possibly_batched_index]
File "/DATA/zcl/myConda/miniconda/envs/BBCU/lib/python3.8/site-packages/torch/utils/data/_utils/fetch.py", line 58, in
data = [self.dataset[idx] for idx in possibly_batched_index]
File "/DATA/zcl/program/BBCU-master/BBCU-denoiseAndblocking/data/dataset_dncnn.py", line 44, in getitem
img_H = pickle.load(_f)
_pickle.UnpicklingError: A load persistent id instruction was encountered,
but no persistent_load function was specified.

When I execute ‘’CUDA_VISIBLE_DEVICES=0 python3 main_train_dncnn_denoising_b.py -opt ./options/train_cdncnn_denoising_b.json‘’ why this error？