code: def testUpdateEnvInWorker(self):
      with self.assertRaises(ValueError):
          combinations.env().tf_data_service_dispatcher = "localhost"
  
imports: import importlib
  import os
  import sys
  import unittest
  from absl.testing import parameterized
  from tensorflow.python.distribute import combinations
  from tensorflow.python.distribute import test_util
  from tensorflow.python.distribute.cluster_resolver import tfconfig_cluster_resolver
  from tensorflow.python.eager import context
  from tensorflow.python.framework import combinations
  from tensorflow.python.platform import test
label_desc: Use image node_id 3 for calling the ClusterCombinationTestEnvTest obj's underlying member method code with example usage: obj.testUpdateEnvInWorker() without return types