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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 async def close_async(self):
 """Close async connection. """

        if self._async_wait:
            await self._async_wait
        if self._async_conn:
            conn = self._async_conn
            self._async_conn = None
            self._async_wait = None
            self._task_data = None
            await conn.close()