The solution implemented in MOTOR-902 uses:

        return asyncio.get_event_loop_policy().get_event_loop()

to attempt to workaround https://bugs.python.org/issue39529

This was pointed out to us as problematic by a (the?) Tornado maintainer here: https://github.com/mongodb/motor/pull/170

The gist is that even though asyncio.get_event_loop_policy().get_event_loop() is not deprecated in Python yet, it will break when the asyncio.get_event_loop() behavior is changed (planned for Python 3.12). We want users to see DeprecationWarnings when using motor incorrectly like this:

>>> import motor.motor_asyncio
>>> client = motor.motor_asyncio.AsyncIOMotorClient()
>>> client.test.pages.drop()  # this should raise a DeprecationWarning because it was called without a running loop