tornado与mysql连接

import tornado.ioloop
import tornado.web
import aiomysql

async def setup_db():
    return await aiomysql.create_pool(
        host='127.0.0.1',
        port=3306,
        user='root',
        password='password',
        db='test',
        loop=tornado.ioloop.IOLoop.current().asyncio_loop
    )

class MainHandler(tornado.web.RequestHandler):
    async def get(self):
        async with self.settings['db'].acquire() as conn:
            async with conn.cursor() as cur:
                await cur.execute("SELECT * FROM users")
                result = await cur.fetchall()
                self.write(str(result))

def make_app():
    return tornado.web.Application([
        (r"/", MainHandler),
    ], db=setup_db())

if __name__ == "__main__":
    app = make_app()
    app.listen(8888)
    tornado.ioloop.IOLoop.current().start()