GetIndicator函想获取可变周期的均线MA(i)，如i=1时MA(1),i=5时MA(5)
报错，寻求解决方案~~

if i <=26:
i =26
MA = GetIndicator('MA', g.code, params = (i,120), bar_type = BarType.Min5)
MA_i_buy =MA['MA(i)']
MA_120 = MA['MA(120)']

ERROR - Traceback (most recent call last):
File "./Envelop.py", line 101, in OnBar
return Main.OnBar(context, code, bartype)
File "", line 165, in OnBar
KeyError: 'MA(i)'