Is RoBERTa's pair of sequences tokenizer correct with double </s>
In RoBERTa's build_input_with_special_tokens, the comment says 
 
```    
A RoBERTa sequence has the following format:
single sequence: <s> X </s>
pair of sequences: <s> A </s></s> B </s>
```

I find the double `</s></s>` very peculiar. Can you please verify that it should not be `</s><s>` (as a normal XML tag).

Thank you for the amazing work here.
Yes, this is how RoBERTa was trained. 