code: def look_up_named_module(name: str, mod, print_all_options=False):
      """
      get the named module in `mod` by the attribute name,
      for example ``look_up_named_module(net, "features.3.1.attn")``
  
      Args:
          name: a string representing the module attribute.
          mod: a pytorch module to be searched (in ``mod.named_modules()``).
          print_all_options: whether to print all named modules when `name` is not found in `mod`. Defaults to False.
  
      Returns:
          the corresponding pytorch module's subcomponent such as ``net.features[3][1].attn``
      """
      name_str = look_up_option(
          name,
          {n[0] for n in mod.named_modules()},
          default=None,
          print_all_options=print_all_options,
      )
      if name_str is None:
          return None
      if name_str == "":
          return mod
      for n in name_str.split("."):
          if n.isdigit():
              mod = mod[int(n)]
          else:
              n = look_up_option(
                  n,
                  {item[0] for item in mod.named_modules()},
                  default=None,
                  print_all_options=False,
              )
              if n is None:
                  return None
              mod = getattr(mod, n)
      return mod
  
imports: from __future__ import annotations
  import io
  import re
  import warnings
  from collections import OrderedDict
  from collections.abc import Callable, Mapping, Sequence
  from contextlib import contextmanager
  from copy import deepcopy
  from typing import Any
  import numpy
  import torch
  import torch.nn
  from monai.apps.utils import get_logger
  from monai.config import PathLike
  from monai.utils.misc import ensure_tuple, save_obj, set_determinism
  from monai.utils.module import look_up_option, optional_import, pytorch_after
  from monai.utils.type_conversion import convert_to_dst_type, convert_to_tensor
label_desc: Use image node_id 2 for calling a global function with example usage: look_up_named_module(name, mod, print_all_options) and returns: mod, None, mod, None