code: def S2(self):
      ''' 量縮價跌 '''
      return self.a.stock_vol[-1] < self.a.stock_vol[-2] and not self.a.PUPTf S2(self):
      ''' 量縮價跌 '''
      return self.a.stock_vol[-1] < self.a.stock_vol[-2] and not self.a.PUPTY
docs: 量縮價跌