code: def _create_actor(self):
      for _ in range(2):
          actor = Actor()
          ret = actor.add_one(1)
          self.assertEqual(ret, 2)
  
imports: import unittest
  import parl
  import time
  import threading
  import multiprocessing
  from parl.remote.master import Master
  from parl.remote.worker import Worker
  from parl.remote.client import disconnect
  from parl.utils import get_free_tcp_port, _IS_WINDOWS
label_desc: Use image node_id 3 for calling the TestCluster obj's underlying member method code with example usage: obj._create_actor() without return types