code: def test_is_cached(self):
      tempdir = self.create_tempdir()
      cache_files = dataset_util.get_cache_files_coco(
          tasks_test_utils.get_test_data_path("coco_data"),
          cache_dir=tempdir,
      )
      self.assertFalse(cache_files.is_cached())
      with open(cache_files.tfrecord_files[0], "w") as f:
          f.write("test")
      self.assertFalse(cache_files.is_cached())
      with open(cache_files.metadata_file, "w") as f:
          f.write("test")
      self.assertTrue(cache_files.is_cached())
  
imports: import hashlib
  import json
  import os
  import shutil
  from unittest import mock
  import tensorflow
  from mediapipe.model_maker.python.vision.core import test_utils
  from mediapipe.model_maker.python.vision.object_detector import dataset_util
  from mediapipe.tasks.python.test import test_utils
label_desc: Use image node_id 10 for calling the DatasetUtilTest obj's underlying member method code with example usage: obj.test_is_cached() without return types