code: def forward(self, x):
      return self.head(self.blocks(self.stem(x)))
  
imports: import contextlib
  import pytest
  import torch
  import torch.multiprocessing
  import torch.nn
  from torch.nn.parallel import DistributedDataParallel
  import torch.optim
  from fairscale.fair_dev.testing.testing import dist_init, dump_all_tensors, skip_if_single_gpu, teardown, temp_files_ctx
  from fairscale.internal import torch_version
  from fairscale.internal.parallel import get_process_group_cached
  from fairscale.nn import checkpoint_wrapper
  from fairscale.nn.data_parallel import FullyShardedDataParallel
  from fairscale.nn.data_parallel import auto_wrap_bn
label_desc: Use image node_id 2 for calling the Model obj's underlying member method code with example usage: obj.forward(x) and returns: self