import asyncio
import os
import time
async def main():
    proc = await asyncio.create_subprocess_exec(
        "/usr/bin/python3", "-c", "import os;os.system('sleep 20')",
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE)
    
    time.sleep(1)
    os.system("ps -f --forest --format pid,ppid,pgid,sid,comm")

    print(f">> This python proces pid={os.getpid()} has a `python3` child process, which has a `sleep` child process.")
    print(f">> Kill the `python3` child process pid={proc.pid}")
    proc.kill()

    os.system("ps -f --forest --format pid,ppid,pgid,sid,comm")
    print(f">> The `python3` child process was killed, the `sleep` process gets orfaned.")
    print(f">> Calling `proc.wait()` or `proc.communicate()` does not return until `sleep` process exits.")
    
    await proc.wait()

asyncio.run(main())