code: def alpha(self):
          
          return round(
              float(
                  self.calc_alpha(
                      self.annualize_return,
                      self.benchmark_annualize_return,
                      self.beta,
                      0.05
                  )
              ),
              2
          )
docs: alpha比率 与市场基准收益无关的超额收益率