code: def best_four_point_to_sell(self):
          
          result = []
          if self.check_plus_bias_ratio() and \
              (self.best_sell_1() or self.best_sell_2() or self.best_sell_3() or \
               self.best_sell_4()):
              if self.best_sell_1():
                  result.append(self.best_sell_1.__doc__.strip())
              if self.best_sell_2():
                  result.append(self.best_sell_2.__doc__.strip())
              if self.best_sell_3():
                  result.append(self.best_sell_3.__doc__.strip())
              if self.best_sell_4():
                  result.append(self.best_sell_4.__doc__.strip())
              result = ', '.join(result)
          else:
              result = False
          return result
docs: 判斷是否為四大賣點
  
              :rtype: str or False