RuntimeError: received an empty list of sequences

[alice-create]

When the training epoches starts to evaluate, it will raise this Runtime Error. Hope anyone can help me to solve it.
The detail of the error message is below:
line 567, in evaluate
predicted_docs = [self.predict(doc) for doc in tqdm(val_corpus) if len(doc) != 0]
line 567, in
predicted_docs = [self.predict(doc) for doc in tqdm(val_corpus) if len(doc) != 0]
line 596, in predict
spans, probs = self.model(doc)
line 1102, in _call_impl
return forward_call(*input, **kwargs)
line 423, in forward
states, embeds = self.encoder(doc)
line 1102, in _call_impl
return forward_call(*input, **kwargs)
line 205, in forward
packed, reorder = pack(embeds)
line 73, in pack
packed = pack_sequence(sorted_tensors)
line 398, in pack_sequence
return pack_padded_sequence(pad_sequence(sequences), lengths, enforce_sorted=enforce_sorted)
line 363, in pad_sequence
return torch._C._nn.pad_sequence(sequences, batch_first, padding_value)
RuntimeError: received an empty list of sequences

[Sakura771]

I am using this repository code to reproduce the paper, and I encountered the same RuntimeError(RuntimeError: received an empty list of sequences) as you, did you solve it and how to solve it