code: def testKillAndStartTask(self):
      self.assertTrue(
          context.check_alive("/job:worker/replica:0/task:0")
      )
  
      # It is not allowed to start a task before killing it.
      with self.assertRaises(ValueError):
          self._cluster.start_task("worker", 0)
  
      self._cluster.kill_task("worker", 0)
      self.assertFalse(
          context.check_alive("/job:worker/replica:0/task:0")
      )
  
      # The task is already killed.
      with self.assertRaises(ValueError):
          self._cluster.kill_task("worker", 0)
  
      self._cluster.start_task("worker", 0)
  
      # Without a call to update_server_def, the next check_alive will return
      # False. Alternatively sleeping for 2 seconds here also works.
      context.context().update_server_def(context.get_server_def())
  
      self.assertTrue(
          context.check_alive("/job:worker/replica:0/task:0")
      )
  
file_path: tensorflow-upstream/tensorflow/python/distribute/multi_worker_test_base_test.py
imports: from tensorflow.python.distribute import multi_process_runner
  from tensorflow.python.distribute import multi_worker_test_base
  from tensorflow.python.eager import context
  from tensorflow.python.eager import remote
  from tensorflow.python.eager import test
label_desc: Use image node_id 3 for calling the MultiProcessClusterTest obj's underlying member method code with example usage: obj.testKillAndStartTask() without return types