Yeah, if it gives a NotImplimentedError, then maybe we’ll have that functionality in the future…

I guess I could also define the forward method in the class that receives a ModuleList and adds sequentially?

Actually, you should do that. I omitted that part in my explanation for brevity.

The other thing is I noticed you can pass a list of class objects to nn.Sequential like this guy does here implementing DenseNet in the _make_dense function. Why exactly does this work?

That’s a clever implementation, I would say! Notice that he is not passing the list layers directly to the nn.Sequential, but rather the content of the list layers. That’s why he does nn.Sequential(*layers) instead of nn.Sequential(layers). If you’re not familiar with the usage of a * before a tuple object, please refer to https://stackoverflow.com/questions/11315010/what-do-and-before-a-variable-name-mean-in-a-function-signature 537.
Hope this helps