motor get count
>>> async def do_count():
... n = await db.test_collection.count_documents({})
... print('%s documents in collection' % n)
... n = await db.test_collection.count_documents({'i': {'$gt': 1000}})
... print('%s documents where i > 1000' % n)
...
>>> loop = asyncio.get_event_loop()
>>> loop.run_until_complete(do_count())