LongFormer tokenizer has the same token_type_ids for sequence pairs
Hey Guys,I was trying to process a sequence pair of sentences together using the tokenizer for the longformer model and the problem is that thetoken_type_idsis a list always with zero elements.This is a snippet what the data looks likeScreenshot 2021-12-21 at 00.38.171460×354 48.8 KBThis is the code to create my CustomDataset:class PlagiarismDetectorDataset(Dataset):
    
    def __init__(self, data: pd.DataFrame, tokenizer, max_token_len: int = 4096):
        self.data = data
        self.tokenizer = tokenizer
        self.max_token_len = max_token_len
        
    def __len__(self):
        return len(self.data[self.data['Datatype'] == 'train'])
    
    def __getitem__(self, item: int):
        
        data_row = self.data.iloc[item]
        
        review = data_row.Text
        original = self.data[(self.data['Task'] == data_row.Task) & (self.data.Datatype == 'orig')]['Text'].iloc[0]
        label = data_row.Class
        
        encoding = self.tokenizer(
            text=review,
            text_pair=original,
            add_special_tokens=True,
            max_length=self.max_token_len,
            return_token_type_ids=True,
            truncation=True,
            return_attention_mask=True,
            return_tensors="pt")
        
        return dict(
            review=review,
            original=original,
            label=label,
            input_ids=encoding["input_ids"].flatten(),
            token_type_ids=encoding["token_type_ids"].flatten(),
            attention_mask=encoding["attention_mask"].flatten(),
            labels=torch.DoubleTensor(label)
        )Finally, this the way to get a sample of the processed data:from transformers import AutoTokenizer, LongformerForSequenceClassification
tokenizer = AutoTokenizer.from_pretrained('allenai/longformer-base-4096')

train_dataset = PlagiarismDetectorDataset(data=aux, tokenizer=tokenizer)
sample_data = train_dataset[0]Based on thevideo of preprocessingI was expecting to have atoken_type_idswith 0 and 1 elements. However, the result I get is a list of zero elements. What am I doing wrong?