Solved by JuanFMontesinos in post #4 
              
              
                Yes. That’s it. A last detail is this only works for single-input layers. 
As you can see in the source code of its forward function: 
    def forward(self, input):
        for module in self:
            input = module(input)
        return input

Aaand a minor correction: 

in which 【layers】 are a…