获取多个k线后出现了“Task was destroyed but it is pending!”的异常

貌似是python协程机制的锅，可能是我获取的K线太多了，获取K线用完后怎么安全地取消获取K线的任务啊？

它提示抛出异常的代码块为TqApi类里定义的

async def _get_serial_async(self, symbol, chart_id, serial, pack):
        await self._ensure_symbol_async(symbol)
        self._auth._has_md_grants(symbol)
        # 判断用户是否指定了 chart_id（参数）, 如果指定了，则一定会发送新的请求。
        if serial is None or chart_id is not None:
            self._send_pack(pack)