The usage of the ATLoss

[Onion12138]

Thanks for your amazing work!
I am very interested in the ATLoss, but there is a little question I want to ask.
When using the ATLoss, should we add a no-relation label?
For example, there are 26 relation types, the gold labels may contain multiple relation types, but at least one relation type.
How to represent the no-relation? Show I create a tensor of size 27 and set the first label 1 or a tensor of size 26 and set all the labels zero?
Look forward to your reply. Many Thanks,