So when we perform a model(...) call, it actually ends up calling model.forward(...). What you’re seeing here is that it’s calling that method (line 550) but apparently your Net_do model does not have such a method. Therefore your model instead inherits the forward method from its parent (nn.Module) which raises the NotImplementedError.
Does your Net_do have a forward method? If so, can you please post the class code for Net_do?