code: def test_current_actor(ray_start_regular):
      @ray.remote
      class Echo:
          def __init__(self):
              pass
  
          def echo(self, s):
              self_actor = ray.get_runtime_context().current_actor
              return self_actor.echo2.remote(s)
  
          def echo2(self, s):
              return s
  
      e = Echo.remote()
      obj = e.echo.remote("hello")
      assert ray.get(ray.get(obj)) == "hello"
  
imports: import ray
  import os
  import signal
  import time
  import sys
  import pytest
  import warnings
  from ray._private.test_utils import SignalActor
  from ray.util.scheduling_strategies import PlacementGroupSchedulingStrategy
  from ray.util.state import list_tasks
  from ray._private.test_utils import wait_for_condition
label_desc: Use image node_id 3 for calling a global function with example usage: test_current_actor(ray_start_regular) and returns: self_actor, s