When does one divide by the meta_batch_size for MAML during meta-learning?

I was going through the maml example in the higher library but it seems to me they are forgetting to divide by the meta_batch_size, they have:

qry_loss.backward()

where they should have

meta_batch_size = qry_loss.size(0)
(qry_loss/meta_batch_size).backward()

is this correct? should they be dividing by the meta_batch_size?

references: