code: def test_offline_mode_sharded_checkpoint(self):
      # this test is a bit tricky since TRANSFORMERS_OFFLINE can only be changed before
      # `transformers` is loaded, and it's too late for inside pytest - so we are changing it
      # while running an external program
  
      # python one-liner segments
  
      # this must be loaded before socket.socket is monkey-patched
      load = """
  from transformers import BertConfig, BertModel, BertTokenizer
          """
  
      run = """
  mname = "hf-internal-testing/tiny-random-bert-sharded"
  BertConfig.from_pretrained(mname)
  BertModel.from_pretrained(mname)
  print("success")
          """
  
      mock = """
  import socket
  def offline_socket(*args, **kwargs): raise socket.error("Offline mode is enabled")
  socket.socket = offline_socket
          """
  
      # baseline - just load from_pretrained with normal network
      cmd = [sys.executable, "-c", "\n".join([load, run])]
  
      # should succeed
      env = self.get_env()
      result = subprocess.run(
          cmd, env=env, check=False, capture_output=True
      )
      self.assertEqual(result.returncode, 0, result.stderr)
      self.assertIn("success", result.stdout.decode())
  
      # next emulate no network
      cmd = [sys.executable, "-c", "\n".join([load, mock, run])]
  
      # Doesn't fail anymore since the model is in the cache due to other tests, so commenting this.
      # env["TRANSFORMERS_OFFLINE"] = "0"
      # result = subprocess.run(cmd, env=env, check=False, capture_output=True)
      # self.assertEqual(result.returncode, 1, result.stderr)
  
      # should succeed as TRANSFORMERS_OFFLINE=1 tells it to use local files
      env["TRANSFORMERS_OFFLINE"] = "1"
      result = subprocess.run(
          cmd, env=env, check=False, capture_output=True
      )
      self.assertEqual(result.returncode, 0, result.stderr)
      self.assertIn("success", result.stdout.decode())
  
imports: import subprocess
  import sys
  from transformers.testing_utils import TestCasePlus, require_torch
label_desc: Use image node_id 2 for calling the OfflineTests obj's underlying member method code with example usage: obj.test_offline_mode_sharded_checkpoint() without return types