How can you unsqueeze a 2+d tensor at once?
In [1]: import torch                                                                                                                                                                                                                           

In [2]: im = torch.Tensor(40,40)                                                                                                                                                                                                               

In [3]: im.size()                                                                                                                                                                                                                              
Out[3]: torch.Size([40, 40])

In [4]: im.view(1,1,-1).size()                                                                                                                                                                                                                 
Out[4]: torch.Size([1, 1, 1600])

im.view(1,1,-1,-1) throws an error. Best I came up with is im.view((1,1) + im.size()).size(), but that just looks ugly.