text: from enum import Enum
  
  EXCHANGE = {
      "CZCE": "郑州商品交易所",
      "DCE": "大连商品交易所",
      "SHFE": "上海期货交易所",
      "CFFEX": "中国金融期货交易所"
  }
  
  
  class FreqCode(Enum):
      DAY = "D"
      WEEK = "W"
      MONTH = "M"
  