# indie:lang_version = 5
from indie import indicator, param, plot, color
from indie.algorithms import Ema


@indicator('BBP')  # Bull Bear Power
@param.int('length', default=13, min=1)
@plot.line(color=color.BLUE)
def Main(self, length):
    bear_power = self.low[0] - Ema.new(self.close, length)[0]
    bull_power = self.high[0] - Ema.new(self.close, length)[0]
    return bull_power + bear_power