code: def testChooseFromDatasets(self, num_workers):
      cluster = data_service_test_base.TestCluster(
          num_workers=num_workers
      )
      words = [b"foo", b"bar", b"baz"]
      datasets = [
          dataset_ops.Dataset.from_tensors(w).repeat() for w in words
      ]
      choice_array = np.random.randint(3, size=(15,), dtype=np.int64)
      choice_dataset = dataset_ops.Dataset.from_tensor_slices(
          choice_array
      )
      ds = dataset_ops.Dataset.choose_from_datasets(
          datasets, choice_dataset
      )
      ds = self._make_dynamic_sharding_dataset(ds, cluster)
      expected = [words[i] for i in choice_array] * num_workers
  
      assert_items_equal = num_workers > 1
      self.assertDatasetProduces(
          ds, expected, assert_items_equal=assert_items_equal
      )
  
imports: import collections
  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.kernel_tests import test_base
  from tensorflow.python.data.kernel_tests import tf_record_test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import readers
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import errors
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 22 for calling the DynamicShardingTest obj's underlying member method code with example usage: obj.testChooseFromDatasets(num_workers) without return types