code: def test_multiple_refs_for_same_file(self):
      with SoftTemporaryDirectory() as cache:
          hf_hub_download(
              MODEL_IDENTIFIER, "file_0.txt", cache_dir=cache
          )
          hf_hub_download(
              MODEL_IDENTIFIER,
              "file_0.txt",
              cache_dir=cache,
              revision="file-2",
          )
  
          expected_directory_name = (
              f'models--{MODEL_IDENTIFIER.replace("/", "--")}'
          )
          expected_path = os.path.join(cache, expected_directory_name)
  
          refs = os.listdir(os.path.join(expected_path, "refs"))
          refs.sort()
  
          snapshots = os.listdir(
              os.path.join(expected_path, "snapshots")
          )
          snapshots.sort()
  
          # Directory should contain two revisions
          self.assertListEqual(refs, ["file-2", "main"])
  
          refs_contents = [
              get_file_contents(os.path.join(expected_path, "refs", f))
              for f in refs
          ]
          refs_contents.sort()
  
          # snapshots directory should contain two snapshots
          self.assertListEqual(refs_contents, snapshots)
  
          snapshot_links = [
              os.readlink(
                  os.path.join(
                      expected_path, "snapshots", filename, "file_0.txt"
                  )
              )
              for filename in snapshots
          ]
  
          # All snapshot links should point to the same file.
          self.assertEqual(*snapshot_links)
  
imports: import os
  import time
  import unittest
  from io import BytesIO
  from huggingface_hub import HfApi, hf_hub_download, snapshot_download
  from huggingface_hub.utils import SoftTemporaryDirectory, logging
  from huggingface_hub.utils._errors import EntryNotFoundError
  from .testing_constants import ENDPOINT_STAGING, TOKEN
  from .testing_utils import repo_name, with_production_testing, xfail_on_windows
label_desc: Use image node_id 5 for calling the CacheFileLayoutHfHubDownload obj's underlying member method code with example usage: obj.test_multiple_refs_for_same_file() without return types