code: def get_alpha(self, *args):
          
          for x in args:
              self.EF += get_ef(self._unit, x)
          molecular = self.PTN + self.EF - self.SCN + 1
          denominator = self.NN + self.SPN + self.SCN - self.EF + 1
          if molecular <= 0:
              molecular = 1
          if denominator <=0:
              denominator = 1
          fraction = molecular / denominator
          if args:
              alpha = ln(fraction)
              log('debug',
                  '当前参数如下：\n文本行：【{}】\n纯文本数：【{}】，强化因子：【{}】，数字数：【{}】，特殊字符数：【{}】，特殊中文字符：【{}】，字符数：【{}】\n风险因子：【{}】，句数：【{}】'.format(
                      self._unit, self.PTN, self.EF, self.NN, self.SPN, self.SCN, self.NC, alpha, self.SN))
          else:
              alpha = ln(fraction) + self.SN
              log('debug',
                  '当前参数如下：\n文本行：【{}】\n纯文本数：【{}】，句数：【{}】，数字数：【{}】，特殊字符数：【{}】，特殊中文字符：【{}】，字符数：【{}】\n风险因子：【{}】'.format(
                      self._unit, self.PTN, self.SN, self.NN, self.SPN, self.SCN, self.NC, alpha))
          return alpha
docs: 计算风险因子
  
          Return:
          alpha               -- 风险因子，float类型