code: def get_initial_file_loader():
      """get file loader for first stage loading
      Some loaders are used to establish skelecton of whole nnabla graph,
      they should be performed for this first stage.
      """
      file_loaders = OrderedDict(
          [
              (".nntxt,.prototxt", _nntxt_file_loader),
              (".protobuf,.h5", _parameter_file_loader),
              (".nnp", _nnp_file_loader),
              (".optimizer", _opti_file_rough_loader),
          ]
      )
      return file_loaders
  
imports: import contextlib
  import io
  import os
  import re
  import zipfile
  from collections import OrderedDict
  from functools import partial
  import google.protobuf.text_format
  import h5py
  import nnabla
  import numpy
  from nnabla.logger import logger
  from nnabla.utils import nnabla_pb2
  from nnabla.utils.nnp_format import nnp_version
label_desc: Use image node_id 15 for calling a global function with example usage: get_initial_file_loader() and returns: file_loaders