code: def _assert_cache_files_equal(self, cf1, cf2):
      self.assertEqual(cf1.cache_prefix, cf2.cache_prefix)
      self.assertEqual(cf1.num_shards, cf2.num_shards)
  
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 1 for calling the DatasetUtilTest obj's underlying member method code with example usage: obj._assert_cache_files_equal(cf1, cf2) without return types