code: def forward(self, input_tensor, gt):
      y = self.linear(input_tensor)
      loss = self.loss(y, gt)
      return loss
  
file_path: apex/apex/contrib/test/optimizers/test_distributed_fused_lamb.py
imports: import os
  import inspect
  import torch
  from torch.cuda.amp import GradScaler
  from torch.testing._internal import common_utils
  from apex.parallel.distributed import flat_dist_call
  from apex.contrib.optimizers.distributed_fused_lamb import DistributedFusedLAMB
  from apex.transformer.testing.distributed_test_base import NcclDistributedTestBase
label_desc: Use image node_id 2 for calling the ModelFoo obj's underlying member method code with example usage: obj.forward(input_tensor, gt) and returns: loss