Tushare 日期数据格式为 YYYYMMDD，我在VN Trander 的数据管理从CSV文件导入数据设置对话框中时间格式设为YYYYMMDD，出现以下出错信息，请问怎么处理？谢谢！
Traceback (most recent call last):
File "c:\vnstudio\lib\site-packages\vnpy\app\data_manager\ui\widget.py", line 230, in import_data
datetime_format
File "c:\vnstudio\lib\site-packages\vnpy\app\data_manager\engine.py", line 54, in import_data_from_csv
dt = datetime.strptime(item[datetime_head], datetime_format)
File "c:\vnstudio\lib_strptime.py", line 577, in _strptime_datetime
tt, fraction, gmtoff_fraction = _strptime(data_string, format)
File "c:\vnstudio\lib_strptime.py", line 359, in _strptime
(data_string, format))
ValueError: time data 'CU1811.SHF' does not match format 'YYYYMMDD'