code: def test_kill_issue43884(self):
      if sys.platform == "win32":
          blocking_shell_command = (
              f'{sys.executable} -c "import time; time.sleep(2)"'
          )
      else:
          blocking_shell_command = "sleep 1; sleep 1"
      creationflags = 0
      if sys.platform == "win32":
          from subprocess import CREATE_NEW_PROCESS_GROUP
  
          # On windows create a new process group so that killing process
          # kills the process and all its children.
          creationflags = CREATE_NEW_PROCESS_GROUP
      proc = self.loop.run_until_complete(
          asyncio.create_subprocess_shell(
              blocking_shell_command,
              stdout=asyncio.subprocess.PIPE,
              creationflags=creationflags,
          )
      )
      self.loop.run_until_complete(asyncio.sleep(1))
      if sys.platform == "win32":
          proc.send_signal(signal.CTRL_BREAK_EVENT)
      # On windows it is an alias of terminate which sets the return code
      proc.kill()
      returncode = self.loop.run_until_complete(proc.wait())
      if sys.platform == "win32":
          self.assertIsInstance(returncode, int)
          # expect 1 but sometimes get 0
      else:
          self.assertEqual(-signal.SIGKILL, returncode)
  
imports: import os
  import signal
  import sys
  import textwrap
  import unittest
  import warnings
  from unittest import mock
  import asyncio
  from asyncio import base_subprocess
  from asyncio import subprocess
  from test.test_asyncio import utils
  from test import support
  from test.support import os_helper
label_desc: Use image node_id 7 for calling the SubprocessMixin obj's underlying member method code with example usage: obj.test_kill_issue43884() without return types