Thank you for your reply, but I do get the torch.Tensor.
Here is part of my code:
    def forward(self, x):
        # Explicitly forward every layer.
        # Branch2a.
        in_channel = x.size(1)
        l_size = list(x.size())
        import torch
        fake = torch.ones(3,4,5).cuda()
        type(fake.size(2))
        import pdb; pdb.set_trace()