code: def forward(self, input):
      self.loss = F.mse_loss(input, self.target)
      return input
  
imports: from __future__ import print_function
  import os
  import torch
  import torch.nn
  import torch.nn.functional
  import torch.optim
  from PIL import Image
  import matplotlib.pyplot
  import torchvision.transforms
  import torchvision.models
  import copy
  from clearml import Task
label_desc: Use image node_id 2 for calling the ContentLoss obj's underlying member method code with example usage: obj.forward(input) and returns: input