# indie:lang_version = 5
from indie import indicator, format, param, plot, color, MutSeriesF
from indie.algorithms import Ema, Sum
from indie.math import divide


@indicator('Mass Index', format=format.PRICE)
@param.int('length', default=10, min=1)
@plot.line(color=color.BLUE)
def Main(self, length):
    span = MutSeriesF.new(self.high[0] - self.low[0])
    ema1 = Ema.new(span, 9)
    ema2 = Ema.new(ema1, 9)
    return Sum.new(MutSeriesF.new(divide(ema1[0], ema2[0])), length)[0]