code: def moving_average(self, data, days):
          
          result = []
          data = data[:]
          for dummy in range(len(data) - int(days) + 1):
              result.append(round(sum(data[-days:]) / days, 2))
              data.pop()
          result.reverse()
          return result
docs: 計算移動平均數
  
              :rtype: 序列 舊→新