2020-12-16 13:06:13.627305 开始加载历史数据
2020-12-16 13:06:18.936016 加载进度：###### [60%]
2020-12-16 13:06:21.810235 加载进度：########## [100%]
2020-12-16 13:06:21.810235 历史数据加载完成，数据量：15796
2020-12-16 13:06:21.810235 触发异常，回测终止
2020-12-16 13:06:21.812234 Traceback (most recent call last):
File "c:\Users\yuanh\Documents\GitHub\vnpy\vnpy\app\cta_strategy\backtesting.py", line 288, in run_backtesting
self.callback(data)
TypeError: 'NoneType' object is not callable
可能是什么原因？
def load_bar(
self,
vt_symbol: str,
days: int,
interval: Interval,
callback: Callable,
use_database: bool
):
""""""
self.days = days
self.callback = callback
