What do i, batch, and step represent? what differences are there?
for i, batch in enumerate(dataloader):
        real_A = Variable(batch["A"].type(Tensor))
        real_B = Variable(batch["B"].type(Tensor))

for step, (x, y) in enumerate(data_loader):
            images = make_variable(x)
            labels = make_variable(y.squeeze_())