code: def test_sentinel(self):
      p = Process(target=time.sleep, args=(0.2,), name="test_sentinel")
      p.start()
      fds = select.select([p.sentinel], [], [], 0.1)
      assert len(fds[0]) == 0
      fds = select.select([p.sentinel], [], [])
      assert len(fds[0]) == 1
      assert fds[0][0] == p.sentinel
      p.join()
  
imports: import pytest
  import time
  import math
  import select
  import fiber
  import docker
  import requests
  from fiber import Process
  from fiber.docker_backend import Backend
  import fiber.config
label_desc: Use image node_id 13 for calling the TestBasic obj's underlying member method code with example usage: obj.test_sentinel() without return types