runtime error in preprocess.py: does not have a __getstate__ method defined

[accocca]

I run the code in preprocess.py and it has an error:
Traceback (most recent call last): File "preprocess.py", line 92, in <module> preprocess(**vars(PARSER.parse_args())) File "preprocess.py", line 71, in preprocess for speaker_name, mel_tensor in tqdm(dataloader, ncols=0, desc="Preprocess"): File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/site-packages/tqdm/std.py", line 1178, in __iter__ for obj in iterable: File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 359, in __iter__ return self._get_iterator() File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 305, in _get_iterator return _MultiProcessingDataLoaderIter(self) File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/site-packages/torch/utils/data/dataloader.py", line 918, in __init__ w.start() File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/multiprocessing/process.py", line 121, in start self._popen = self._Popen(self) File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/multiprocessing/context.py", line 224, in _Popen return _default_context.get_context().Process._Popen(process_obj) File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/multiprocessing/context.py", line 283, in _Popen return Popen(process_obj) File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/multiprocessing/popen_spawn_posix.py", line 32, in __init__ super().__init__(process_obj) File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/multiprocessing/popen_fork.py", line 19, in __init__ self._launch(process_obj) File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/multiprocessing/popen_spawn_posix.py", line 47, in _launch reduction.dump(process_obj, fp) File "/Users/xinyuewang/opt/anaconda3/lib/python3.8/multiprocessing/reduction.py", line 60, in dump ForkingPickler(file, protocol).dump(obj) RuntimeError: Tried to serialize object __torch__.data.wav2mel.Wav2Mel which does not have a __getstate__ method defined!
does anyone know how to solve this?
my version:
python==3.8 torch==1.8.0 torchaudio==0.8.0

[accocca]

already solved.
just change in preprocess.py:
dataloader = DataLoader(dataset, batch_size=1, num_workers=cpu_count())
to
dataloader = DataLoader(dataset, batch_size=1, num_workers=0)
the problem will be solved!