code: def QA_util_get_trade_gap(start, end):
      '返回start_day到end_day中间有多少个交易天 算首尾'
      start, end = QA_util_get_real_datelist(start, end)
      if start is not None:
          return trade_date_sse.index(end) + 1 - trade_date_sse.index(start)
      else:
          return f QA_util_get_trade_gap(start, end):
      '返回start_day到end_day中间有多少个交易天 算首尾'
      start, end = QA_util_get_real_datelist(start, end)
      if start is not None:
          return trade_date_sse.index(end) + 1 - trade_date_sse.index(start)
      else:
          return 0
docs: 返回start_day到end_day中间有多少个交易天 算首尾