Solved by KFrank in post #2 
              
              
                Hi Luuk! 

Yes, but … 

You won’t want to bypass your Own_module backpropagation entirely. 
Suppose Own_module were simply return -input, that is, it just flipped 
the sign of (the gradient of) the loss function?  Then you would be training 
your model to maximize the loss function, your predictions…