Hi @gorev.pv,
So glad you’re enjoying the course!
The comment about detaching the generator is actually intended for inside this function. Remember that you apply the detach() function to the output from the generator - in this case, fake_X, which is one of the parameters passed into get_disc_loss().
For a little more detail, there’s a nice explanation about detaching the generator in this post: Why should we detach the discriminators input ?!