大神们，请问 slow_window能设置超过100吗？如何设置？ 目前一旦设置到120就没有成交记录，为什么呢？
fast_window = 5
slow_window = 20

    self.bg15 = BarGenerator(self.on_bar, 15, self.on_15min_bar)
    self.am15 = ArrayManager()

    self.fast_ma = self.am15.sma(self.fast_window)
    self.slow_ma = self.am15.sma(self.slow_window)