Hello,
Sorry if my question sounds a bit silly, but I just have a question:
I am trying to use LongformerForMultipleChoice model for a multiple-choice question that has 4 options.
When I do:
my_Longformer_multiple_choice_model.encoder.layer[layer_index].forward(hidden_output, 
                                                 attention_mask=my_attention_mask,output_attention=False)

, an this error is generated:

  File "/Users/hyunjindominiquecho/opt/anaconda3/lib/python3.7/site-packages/transformers/modeling_longformer.py", line 384, in _sliding_chunks_query_key_matmul
    batch_size, seq_len, num_heads, head_dim = query.size()

ValueError: too many values to unpack (expected 4)

Here, my_attention_mask is the same attention mask that I would specify under the regular LongformerForMultipleChoice command:
# I am using the LongformerForMultipleChoice model, where each multiple choice question has 4 options.
my_attention_mask = tensor([[[1, 1, 1,  ..., 0, 0, 0],
         [1, 1, 1,  ..., 0, 0, 0],
         [1, 1, 1,  ..., 0, 0, 0],
         [1, 1, 1,  ..., 0, 0, 0]]])
# I can use the my_attention_mask in the regular command as below:
longformer_output= my_Longformer_multiple_choice_model(input_ids=input_ids,....,attention_mask=my_attention_mask)

why is this value error generated? What should I pass for the attention_mask parameter in the command my_Longformer_multiple_choice_model.encoder.layer[layer_index].forward(hidden_output,                                                   attention_mask,output_attention=False)?
Thank you,