code: def info_ratio(self, benchmark, ddof=0):
          
  
          diff = self.excess_ret(benchmark).anlzd_ret()
          return diff / self.tracking_error(benchmark, ddof=ddof)
docs: Information ratio--return per unit of active risk.
  
          Parameters
          ----------
          benchmark : {pd.Series, TSeries, 1d np.ndarray}
              The benchmark security to which `self` is compared.
          ddof : int, default 0
              Degrees of freedom, passed to pd.Series.std().
  
          Returns
          -------
          float