code: def test_read_batch_from_datastore(self):
      class_batches = classification_results.ClassificationBatches(
          self.datastore_client, self.storage_client, ROUND_NAME
      )
      class_batches.init_from_adversarial_batches_write_to_datastore(
          self.submissions, self.adv_batches
      )
      class_batches = classification_results.ClassificationBatches(
          self.datastore_client, self.storage_client, ROUND_NAME
      )
      # read first batch from datastore and verify that only one batch was read
      batch = class_batches.read_batch_from_datastore("CBATCH000000")
      self.assertEqual(0, len(class_batches.data))
      assertCountEqual(
          self,
          ["result_path", "adversarial_batch_id", "submission_id"],
          batch.keys(),
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import unittest
  from six import assertCountEqual
  from eval_lib import classification_results
  from eval_lib import image_batches
  from eval_lib import submissions
  from eval_lib import work_data
  from eval_lib.tests import fake_cloud_client
label_desc: Use image node_id 4 for calling the ClassificationResultsTest obj's underlying member method code with example usage: obj.test_read_batch_from_datastore() without return types