对 asyncpg 连接池使用“async with”时关于 __aexit__ 的属性错误

如何解决对 asyncpg 连接池使用“async with”时关于 __aexit__ 的属性错误

这是我的 Database 类中的一些相关代码：

class Database:

    pool = None

    def __init__(self,dsn):
        loop = asyncio.get_event_loop()
        loop.run_until_complete(self.init_async(dsn))

    async def init_async(self,dsn):
        Database.pool = await asyncpg.create_pool(dsn)

    async def get_connection(self):
        return await Database.pool.acquire()

我认为类上的静态属性是存储连接池的理想方式，以前我每个类实例有一个池，有点击败池的对象。我现在在以下代码中调用 get_connection 时出错：

async def field(self,sql,*values):
    async with await self.get_connection() as conn:
        return await conn.fetchval(sql,*values)

回溯如下：

Traceback (most recent call last):
  File "D:\ProgramData\Anaconda3\lib\site-packages\discord\client.py",line 343,in _run_event
    await coro(*args,**kwargs)
  File "D:\Personal\Python Projects\MusicBot\src\bot\bot.py",line 71,in on_message
    await self.process_commands(msg)
  File "D:\Personal\Python Projects\MusicBot\src\bot\bot.py",line 65,in process_commands
    ctx = await self.get_context(msg,cls=commands.Context)
  File "D:\ProgramData\Anaconda3\lib\site-packages\discord\ext\commands\bot.py",line 852,in get_context
    prefix = await self.get_prefix(message)
  File "D:\ProgramData\Anaconda3\lib\site-packages\discord\ext\commands\bot.py",line 797,in get_prefix
    ret = await discord.utils.maybe_coroutine(prefix,self,message)
  File "D:\ProgramData\Anaconda3\lib\site-packages\discord\utils.py",line 331,in maybe_coroutine
    return await value
  File "D:\Personal\Python Projects\MusicBot\src\bot\bot.py",line 61,in prefix
    prefix = await self._fetch_prefix(msg)
  File "D:\Personal\Python Projects\MusicBot\src\bot\bot.py",line 75,in _fetch_prefix
    prefix = await self.db.field("SELECT cmd_prefix FROM guild WHERE guild_id = $1",id)
  File "D:\Personal\Python Projects\MusicBot\src\db\database.py",line 35,in field
    async with await self.get_connection() as conn:
AttributeError: __aexit__

看起来我的 get_connection 对 async with 过敏。如果我用一个普通的 async with 替换 await 然后东西再次工作：

async def field(self,*values):
    conn = await self.get_connection()
    return await conn.fetchval(sql,*values)

我收到 __aexit__ 的属性错误有什么问题？

我已被转介到 this question，但我无法“适合”问题中的代码结构以及我的方案的给定答案。