VNPY2.5，在调用aroon指标时第二行报错 IndexError: invalid index to scalar variable.
aroon_up, aroon_down = am.aroon(self.n_window)
self.aroon_up0 = aroon_up[-1]
self.aroon_up1 = aroon_up[-2]
self.aroon_down0 = aroon_down[-1]
self.aroon_down1 = aroon_down[-2]百度了半天也没找到啥有效的说法。请教各位大佬，应该是什么问题？谢谢谢谢！
self.aroon0 = self.aroon_up0 - self.aroon_down0
