code: def forward(self, batch):
      return (self.l1(batch) - batch.mean(dim=1)).mean()
  
imports: import os
  import shutil
  import pytest
  import torch
  from omegaconf import OmegaConf
  from pytorch_lightning import Trainer
  from nemo.core import ModelPT
  from nemo.utils import logging
  from nemo.utils.exp_manager import CallbackParams, ExpManagerConfig, StatelessTimer, exp_manager
label_desc: Use image node_id 5 for calling the ExampleModel obj's underlying member method code with example usage: obj.forward(batch) and returns: unknown