docstr: Test to make sure basic sychronous calls to remote workers work.
docstr_tok: ["Test","to","make","sure","basic","sychronous","calls","to","remote","workers","work","."]
code: def test_foreach_worker(self):
      """Test to make sure basic sychronous calls to remote workers work."""
      ws = WorkerSet(
          env_creator=lambda _: gym.make("CartPole-v1"),
          default_policy_class=RandomPolicy,
          config=AlgorithmConfig().rollouts(num_rollout_workers=2),
          num_workers=2,
      )
  
      policies = ws.foreach_worker(
          lambda w: w.get_policy(DEFAULT_POLICY_ID),
          local_worker=True,
      )
  
      # 3 policies including the one from the local worker.
      self.assertEqual(len(policies), 3)
      for p in policies:
          self.assertIsInstance(p, RandomPolicy)
  
      policies = ws.foreach_worker(
          lambda w: w.get_policy(DEFAULT_POLICY_ID),
          local_worker=False,
      )
  
      # 2 policies from only the remote workers.
      self.assertEqual(len(policies), 2)
  
      ws.stop()
  
file_path: ray/rllib/evaluation/tests/test_worker_set.py
imports: import gymnasium
  import unittest
  import ray
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig
  from ray.rllib.evaluation.worker_set import WorkerSet
  from ray.rllib.examples.policy.random_policy import RandomPolicy
  from ray.rllib.policy.sample_batch import DEFAULT_POLICY_ID
label_desc: Use image node_id 3 for calling the TestWorkerSet obj's underlying member method code with example usage: obj.test_foreach_worker() without return types