You cannot call cpu() on a Python tuple, as this is a method of PyTorch’s tensors.
If you want to move all internal tuples to the CPU, you would have to call it on each of them:
x = (torch.randn([1, 3, 244, 244]).cuda(),
     torch.randn([1, 244, 244]).cuda(),
     torch.randn([1, 244, 244]).cuda())

x.cpu() # error

y = tuple(t.cpu() for t in x)
print(y)