code: def reverse(self, output):
      if self.training and self.initialized.item() == 0:
          if not self.allow_reverse_init:
              raise RuntimeError(
                  "Initializing ActNorm in reverse direction is "
                  "disabled by default. Use allow_reverse_init=True to enable."
              )
          else:
              self.initialize(output)
              self.initialized.fill_(1)
  
      if len(output.shape) == 2:
          output = output[:, :, None, None]
          squeeze = True
      else:
          squeeze = False
  
      h = output / self.scale - self.loc
  
      if squeeze:
          h = h.squeeze(-1).squeeze(-1)
      return h
  
file_path: generative-models/sgm/modules/autoencoding/lpips/util.py
imports: import hashlib
  import os
  import requests
  import torch
  import torch.nn
  from tqdm import tqdm
label_desc: Use image node_id 4 for calling the ActNorm obj's underlying member method code with example usage: obj.reverse(output) and returns: h