code: def _check_module(module):
      """
      检查该 module 是否含有 某个 backend 的特征
  
      :param module: module 对象
      :return:
      """
      try:
          file = module.__file__
          for backend in SUPPORT_BACKENDS:
              if f"{os.sep}site-packages{os.sep}{backend}" in file:
                  return backend
              if f"{os.sep}dist-packages{os.sep}{backend}" in file:
                  return backend
      except:
          pass
      return None
  
file_path: fastNLP/fastNLP/core/dataloaders/prepare_dataloader.py
imports: from typing import Union, Callable
  import os
  import sys
  from .torch_dataloader import prepare_torch_dataloader
  from .paddle_dataloader import prepare_paddle_dataloader
  from .jittor_dataloader import prepare_jittor_dataloader
  from .oneflow_dataloader import prepare_oneflow_dataloader
  from ...envs import FASTNLP_BACKEND, SUPPORT_BACKENDS
  from ..log import logger
label_desc: Use image node_id 2 for calling a global function with example usage: _check_module(module) and returns: None, backend, backend