code: def listify_model(
      model: Union[torch.nn.Module, List[torch.nn.Module]]
  ) -> List[torch.nn.Module]:
      if isinstance(model, list):
          return model
      return [model]
  
imports: from typing import Optional, List, Union, Tuple
  import torch
  from torch.nn.parallel import DistributedDataParallel
  from apex.multi_tensor_apply import multi_tensor_applier
  from apex.transformer import parallel_state
  from apex.transformer.enums import ModelType
  from apex.transformer.microbatches import build_num_microbatches_calculator
  from apex.transformer.pipeline_parallel._timers import _Timers
label_desc: Use image node_id 1 for calling a global function with example usage: listify_model(model) and returns: list, model