How to get the image name while running eval Σ(-᷅_-᷄๑) ?

[okusamaOwO]

I'm using det metric and in det_metric.py, the function call receives the batch as one of the parameters:

The batch is a list produced by dataloader, so i came to train.py, which has the dataloaders and i saw:

but i didn't understand how the batch can come from this.

Can someone please tell me where's the batch from ?