Could anybody breakdown the code and explain it to me? The part that needs help is indicated with the "#This part". I would greatly appreciate any help thanks

```
def validation_epoch_end(self, outputs):
    batch_losses = [x["val_loss"]for x in outputs] #This part
    epoch_loss = torch.stack(batch_losses).mean() 
    batch_accs =  [x["val_acc"]for x in outputs]   #This part
    epoch_acc = torch.stack(batch_accs).mean()   
    return {'val_loss': epoch_loss.item(), 'val_acc': epoch_acc.item()}

def epoch_end(self, epoch, result):
    print("Epoch [{}], val_loss: {:.4f}, val_acc: {:.4f}".format( epoch,result['val_loss'], result['val_acc'])) #This part

```