The number of non-linear layers in the network?

[wallykop]

Could you clarify, is there only 1 non-linear layer in your network architecture at the end?

As far as I understood, we are sequentially adding nn.Linear layers to the Sequential list, then, there rises a choice whether to add the activation function (in your Iris example (opened issue), you did not add any activation function, therefore, in fact the whole network is linear in fact). Is it the only non-linearity existing in the network?