code: def start(self, read_only=False):
      assert self.connection_release_task_manager
      return TransactionAsyncContextManager(
          self.pool, read_only, self.connection_release_task_manager
      )
  
imports: import asyncio
  import contextlib
  import functools
  import logging
  import os
  import ssl
  import traceback
  from typing import Any, AsyncIterator, Awaitable, Callable, Dict, Optional, TypeVar
  import aiomysql
  import aiomysql.utils
  import kubernetes_asyncio.client
  import kubernetes_asyncio.config
  import pymysql
  from typing_extensions import Concatenate, ParamSpec
  from gear.metrics import DB_CONNECTION_QUEUE_SIZE, SQL_TRANSACTIONS, PrometheusSQLTimer
  from hailtop.aiotools import BackgroundTaskManager
  from hailtop.auth.sql_config import SQLConfig
  from hailtop.config import get_deploy_config
  from hailtop.utils import first_extant_file, sleep_before_try
label_desc: Use image node_id 2 for calling the Database obj's underlying member method code with example usage: obj.start(read_only) and returns: TransactionAsyncContextManager