docstr: Test probe brings back unhealthy actors.
docstr_tok: ["Test","probe","brings","back","unhealthy","actors","."]
code: def test_probe_unhealthy_actors(self):
      """Test probe brings back unhealthy actors."""
      actors = [Actor.remote(i, maybe_crash=False) for i in range(4)]
      manager = FaultTolerantActorManager(actors=actors)
  
      # Mark first and second actor as unhealthy.
      manager.set_actor_state(1, False)
      manager.set_actor_state(2, False)
  
      # These actors are actually healthy.
      manager.probe_unhealthy_actors(mark_healthy=True)
      # Both actors are now healthy.
      self.assertEqual(len(manager.healthy_actor_ids()), 4)
  
imports: import functools
  import os
  from pathlib import Path
  import pickle
  import sys
  import time
  import unittest
  import ray
  from ray.util.state import list_actors
  from ray.rllib.utils.actor_manager import FaultAwareApply, FaultTolerantActorManager
label_desc: Use image node_id 15 for calling the TestActorManager obj's underlying member method code with example usage: obj.test_probe_unhealthy_actors() without return types