Python3 asyncio is used in threads

the following code simulates the use of two threads to manage event loop:

import time
import asyncio
import threading

async def task(c, i):
    for _ in range(i):
        print(c)
        await asyncio.sleep(1)
    return i

def thread(loop):  -sharp 
    asyncio.set_event_loop(loop)
    asyncio.ensure_future(task("sub thread", 999))
    loop.run_forever()

def main():
    threading.Thread(target=thread, args=(asyncio.get_event_loop(), )).start()

    -sharp 
    future = asyncio.ensure_future(task("main thread", 5))
    while not future.done():
        time.sleep(1)
    print("main done: %s" % future.result())


if __name__ == "__main__":
    main()

its child thread ( thread function) sets and enables a task task 999 times.

in the main thread, a task task is added five times. I set up a While loop to check that the task has finished running, and if so, print out main done: 5 .

< hr >

questions raised:

is there any other solution for multithreaded event loop like this?
in the five task tasks of the main function, I initially tried to use run_until_complete to wait for the end of execution, but a conflict with run_forever resulted in a RuntimeError: This event loop is already running error thrown, so is there any other way to block subsequent code execution besides using the While loop?

< hr >

actual situation description:

I have a program that uses Synchronize + Asynchronous , where the Synchronize program runs on the main thread and async runs on a child thread.
Synchronize and Asynchronous run independently, each performing its own functions. But sometimes you need to use asynchronous functions or methods in Synchronize and get results.

-sharp -*- coding: utf-8 -*- import asyncio from datetime import datetime async def add(a, b): await asyncio.sleep(1) return a + b async def master_thread(loop): print("{} master: 1+2={}".format(datetime.now(), await add(1, 2))) def slave_thread(loop): -sharp : coroutine import time time.sleep(2) f = asyncio.run_coroutine_threadsafe(add(1, 2), loop) print("{} slave: 1+2={}".format(datetime.now(), f.result())) async def main(loop): await asyncio.gather( master_thread(loop), -sharp loop.run_in_executor(None, slave_thread, loop), ) if __name__ == '__main__': loop = asyncio.get_event_loop() loop.run_until_complete(main(loop)) loop.close()