code: def pwm_min_score(self):
          
          if self.min_score is None:
              score = 0
              for row in self.pwm:
                  score += log(min(row) / 0.25 + 0.01)
              self.min_score = score
          
          return self.min_score
docs: Return the minimum PWM score.
  
          Returns
          -------
          score : float
              Minimum PWM score.