code: def __init__(self, num_features, num_layers=1000):
      super().__init__()
      self.fwd = nn.Sequential(
          *[
              GBN(
                  num_features,
                  group_size=2,
                  eps=1e-05,
                  momentum=0.1,
                  affine=True,
                  track_running_stats=True,
              )
              for _ in range(num_layers)
          ]
      )
  
imports: import copy
  import typing
  import unittest
  import torch
  import torch.nn
  from torch.testing._internal import common_utils
  from apex.transformer.testing.distributed_test_base import NcclDistributedTestBase
label_desc: Use image node_id 1 to create a new BNModel object from inherited base classes: nn with example: obj = BNModel(num_features, num_layers)