ValueError: Cell is empty

when i run the commond in ubuntu python preprocess.py -lang_src de -lang_trg en -share_vocab -save_data m30k_deen_shr.pkl An error occurs as follows:

` (att) guest1@GPU2:~/zjl/attention-is-all-you-need-pytorch-master$ python preprocess.py -lang_src de -lang_trg en -share_vocab -save_data m30k_deen_shr.pkl Namespace(data_src=None, data_trg=None, keep_case=False, lang_src='de', lang_trg='en', max_len=100, min_word_count=3, save_data='m30k_deen_shr.pkl', share_vocab=True) [Info] Get source language vocabulary size: 5375 [Info] Get target language vocabulary size: 4556 [Info] Merging two vocabulary ... [Info] Get merged vocabulary size: 9521 [Info] Dumping the processed data to pickle file m30k_deen_shr.pkl Traceback (most recent call last): File "preprocess.py", line 337, in main_wo_bpe() File "preprocess.py", line 332, in main_wo_bpe pickle.dump(data,f) File "/home/guest1/anaconda3/envs/att/lib/python3.6/site-packages/dill/_dill.py", line 267, in dump Pickler(file, protocol, **_kwds).dump(obj) File "/home/guest1/anaconda3/envs/att/lib/python3.6/site-packages/dill/_dill.py", line 454, in dump StockPickler.dump(self, obj)

......

File "/home/guest1/anaconda3/envs/att/lib/python3.6/pickle.py", line 476, in save f(self, obj) # Call unbound method with explicit self File "/home/guest1/anaconda3/envs/att/lib/python3.6/site-packages/dill/_dill.py", line 1177, in save_cell f = obj.cell_contents ValueError: Cell is empty `

How can I solve it?