test.py

from asyncio import Future

callback_list = []

def func(callback):
    callback_list.append(callback)

def func_await():
    future = Future()
    def on_finish():
        future.set_result(None)
    func(on_finish)
    return future

async def test():
    print(1)
    await func_await()
    print(2)

test()
test()

while len(callback_list) != 0:
    callback = callback_list.pop(0)
    callback()