15分钟K线数据缺少 14:45:00 的最后数据

def kline(api, contract, period):
    klines = api.get_kline_serial(contract, period, 60) # 获取k线
    while True:
        api.wait_update()
        print("%s: 开盘：%s, 最高价格：%s, 最低价格：%s, 收盘价格：%s" % (
time_to_str(klines.iloc[-1].datetime), klines.iloc[-1].open, klines.iloc[-1].high, klines.iloc[-1].low, klines.iloc[-1].close))
  api = TqApi(backtest=TqBacktest(start_dt=date(2019, 12, 8), end_dt=date(2019, 12, 8)))
kline(api, "SHFE.rb2001", 15*m)
api.close()