想问一下，我使用系统自带的BollChannel策略回测没有问题，但是放在模拟盘中运行就报错，这该怎么解决呀
[004sc] 触发异常已停止
Traceback (most recent call last):
File "C:\vnstudio\lib\site-packages\vnpy_ctastrategy\engine.py", line 622, in call_strategy_func
func()
File "C:\vnstudio\lib\site-packages\vnpy_ctastrategy\strategies\boll_channel_strategy.py", line 68, in on_init
self.load_bar(10)
File "C:\vnstudio\lib\site-packages\vnpy_ctastrategy\template.py", line 306, in load_bar
use_database
File "C:\vnstudio\lib\site-packages\vnpy_ctastrategy\engine.py", line 589, in load_bar
callback(bar)
File "C:\vnstudio\lib\site-packages\vnpy_ctastrategy\strategies\boll_channel_strategy.py", line 92, in on_bar
self.bg.update_bar(bar)
File "C:\vnstudio\lib\site-packages\vnpy\trader\utility.py", line 266, in update_bar
self.update_bar_minute_window(bar)
File "C:\vnstudio\lib\site-packages\vnpy\trader\utility.py", line 275, in update_bar_minute_window
dt = bar.datetime.replace(second=0, microsecond=0)
AttributeError: 'time.struct_time' object has no attribute 'replace'
