code: def loss(y_pred, y_true):
      return y_pred
  
imports: import unittest
  import torch
  from torch.nn import Module, Linear
  import torch.nn.init
  import torchbearer
  from torchbearer import callbacks
label_desc: Use image node_id 1 for calling a global function with example usage: loss(y_pred, y_true) and returns: y_pred