Trying to use asyncio sqlalchemy it just freeze

Question

I trying to make async database request using sqlalachemy like described in example : https://docs.sqlalchemy.org/en/14/orm/extensions/asyncio.html#synopsis-orm under title : Preventing Implicit IO when Using AsyncSession. As i understood from code exist two ways to create session :

1. using async_session = AsyncSession(engine, expire_on_commit=False)
2. or using sessionmaker with class_=AsyncSession parameter

my code looks like following :

    async def setup_connection(self):
        self.logger.info("Pause to be sure that i am async")
        await asyncio.sleep(1)
        self.logger.info("Async Pause finished")
        self.logger.info("Database engine uri: %s", self.database_engine_uri)
        self.database_engine = create_async_engine(self.database_engine_uri, pool_size=self.pool_size, echo=True)

        async_session = AsyncSession(self.database_engine, expire_on_commit=False)
        self.logger.info("Before hang")
        async with async_session() as session:
            self.logger.info("Inside with")
....

After i execute my code i get following :

2021-06-17 16:07:52,942 File:database.py Function:setup_connection Line:46 Pause to be sure that i am async
2021-06-17 16:07:53,943 File:database.py Function:setup_connection Line:48 Async Pause finished
2021-06-17 16:07:53,943 File:database.py Function:setup_connection Line:49 Database engine uri: mysql+aiomysql://user:[email protected]/db
2021-06-17 16:07:53,954 File:database.py Function:setup_connection Line:53 Before hang

It is feels like code just hang in moment of execution "async with async_session() as session:" because next log message never appear. Can you please help me with proper and simplest way to use asyncio with sqlalachemy.