code: def testLoadWithCustomReaderFunc(self):
      # TODO(b/250921378): Currently, all the unit tests only write one chunk
      # since the test dataset is small. The maximum chunk size is a C++ constant.
      # To test saving/loading multiple chunks in Python, we need a way to inject
      # the maximum chunk size. In this test, we simulate multiple chunks by
      # writing a snapshot and copying its output files.
      cluster = data_service_test_base.TestCluster(num_workers=1)
      dataset = dataset_ops.Dataset.range(10)
      self.evaluate(
          distributed_save_op.distributed_save(
              dataset, self._test_dir, cluster.dispatcher_address()
          )
      )
      _wait_for_snapshot(self._test_dir)
  
      chunks_dir = os.path.join(self._test_dir, "chunks")
      files = os.listdir(chunks_dir)
      for i in range(2):
          for file in files:
              shutil.copy(
                  os.path.join(chunks_dir, file),
                  os.path.join(chunks_dir, f"{file}_{i}"),
              )
  
      def custom_reader_func(datasets):
          datasets = datasets.shuffle(3)
          return datasets.interleave(
              lambda x: x, num_parallel_calls=dataset_ops.AUTOTUNE
          )
  
      dataset = dataset_ops.Dataset.load(
          self._test_dir, reader_func=custom_reader_func
      )
      self.assertDatasetProduces(
          dataset, list(range(10)) * 3, assert_items_equal=True
      )
  
imports: import os
  import shutil
  import tempfile
  import time
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.experimental.kernel_tests.service import test_base
  from tensorflow.python.data.experimental.ops import data_service_ops
  from tensorflow.python.data.experimental.ops import distributed_save_op
  from tensorflow.python.data.experimental.service import _pywrap_snapshot_utils
  from tensorflow.python.data.kernel_tests import checkpoint_test_base
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import errors
  from tensorflow.python.ops import array_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 7 for calling the DistributedSaveTest obj's underlying member method code with example usage: obj.testLoadWithCustomReaderFunc() and returns: datasets