订阅K线时间问题，那个时间点还未开盘

api = TqApi(TqKq(), auth=TqAuth(hp.user_name, hp.password), web_gui='http://127.0.0.1:37585')
ticks = api.get_tick_serial(symbol=symbol, data_length=10)
klines_30m = api.get_kline_serial(symbol=symbol, duration_seconds=60 * 30, data_length=201)
while True:
    api.wait_update()
    if api.is_changing(klines_30m.iloc[-1], ['datetime']):
        print(datetime.datetime.now())  # <==这里居然打印出2022-09-06 20:59:01.068841，这时候不是还没开盘吗？