code: def sleep(self):
      self._send(SleepRequest())
  
imports: import io
  import queue
  import threading
  import time
  import unittest
  import warnings
  import pytest
  from horovod.runner.common.service.task_service import BasicTaskClient, BasicTaskService
  from horovod.runner.common.util import network, secret
  from horovod.runner.util.threads import in_thread
  from horovod.runner.util.streams import Pipe
label_desc: Use image node_id 2 for calling the TestSleepClient obj's underlying member method code with example usage: obj.sleep() without return types