class_docstr: A manager that is aware of the healthiness of remote actors.
  
  .. testcode::
      :skipif: True
  
      import ray
      from ray.rllib.utils.actor_manager import FaultTolerantActorManager
  
      @ray.remote
      class MyActor:
      def apply(self, fn) -> Any:
          return fn(self)
  
      def do_something(self):
          return True
  
      actors = [MyActor.remote() for _ in range(3)]
      manager = FaultTolerantActorManager(
          actors, max_remote_requests_in_flight_per_actor=2,
      )
  
      # Synchronous remote calls.
      results = manager.foreach_actor(lambda actor: actor.do_something())
      # Print results ignoring returned errors.
      print([r.get() for r in results.ignore_errors()])
  
      # Asynchronous remote calls.
      manager.foreach_actor_async(lambda actor: actor.do_something())
      time.sleep(2) # Wait for the tasks to finish.
      for r in manager.fetch_ready_async_reqs()
          # Handle result and errors.
          if r.ok: print(r.get())
          else print("Error: {}".format(r.get()))
class_docstr_tok: ["A","manager","that","is","aware","of","the","healthiness","of","remote","actors",".","..","testcode",":",":",":","skipif",":","True","import","ray","from","ray.rllib.utils.actor_manager","import","FaultTolerantActorManager","@","ray.remote","class","MyActor",":","def","apply","(","self",",","fn",")","-",">","Any",":","return","fn","(","self",")","def","do_something","(","self",")",":","return","True","actors","=","[","MyActor.remote","(",")","for","_","in","range","(","3",")","]","manager","=","FaultTolerantActorManager","(","actors",",","max_remote_requests_in_flight_per_actor=2",",",")","#","Synchronous","remote","calls",".","results","=","manager.foreach_actor","(","lambda","actor",":","actor.do_something","(",")",")","#","Print","results","ignoring","returned","errors",".","print","(","[","r.get","(",")","for","r","in","results.ignore_errors","(",")","]",")","#","Asynchronous","remote","calls",".","manager.foreach_actor_async","(","lambda","actor",":","actor.do_something","(",")",")","time.sleep","(","2",")","#","Wait","for","the","tasks","to","finish",".","for","r","in","manager.fetch_ready_async_reqs","(",")","#","Handle","result","and","errors",".","if","r.ok",":","print","(","r.get","(",")",")","else","print","(","``","Error",":","{","}","''",".format","(","r.get","(",")",")",")"]
docstr: Return the number of healthy remote actors.
docstr_tok: ["Return","the","number","of","healthy","remote","actors","."]
code: def num_healthy_actors(self) -> int:
      """Return the number of healthy remote actors."""
      return sum(
          s.is_healthy for s in self.__remote_actor_states.values()
      )
  
imports: from collections import defaultdict
  import copy
  from dataclasses import dataclass
  import logging
  import sys
  import time
  from typing import Any, Callable, Dict, Iterator, List, Mapping, Optional, Tuple, Union
  import ray
  from ray.actor import ActorHandle
  from ray.exceptions import RayActorError, RayError, RayTaskError
  from ray.rllib.utils.typing import T
  from ray.util.annotations import DeveloperAPI
label_desc: Use image node_id 8 for calling the FaultTolerantActorManager obj's underlying member method code with example usage: obj.num_healthy_actors() and returns: sum