code: def bias_ratio(self, positive_or_negative=False):
          
          return self.data.check_moving_average_bias_ratio(
                                 self.data.moving_average_bias_ratio(3, 6)[0],
                                 positive_or_negative=positive_or_negative)[0]
docs: 判斷乖離
  
              :param bool positive_or_negative: 正乖離 為 True，負乖離 為 False