class_docstr: Defines a PatchGAN discriminator as in Pix2Pix
  --> see https://github.com/junyanz/pytorch-CycleGAN-and-pix2pix/blob/master/models/networks.py
docstr: Standard forward.
docstr_tok: ["Standard","forward","."]
code: def forward(self, input):
      """Standard forward."""
      return self.main(input)
  
imports: import functools
  import torch.nn
  from ..util import ActNorm
label_desc: Use image node_id 2 for calling the NLayerDiscriminator obj's underlying member method code with example usage: obj.forward(input) and returns: self