Motor for mongodb tutorial code example

Example: 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())