楼主，添加启动错误，请分析下什么原因啊

Traceback (most recent call last):
File "d:\programdata\vnstudio\lib\site-packages\vnstation\cli.py", line 90, in run_trader
module = importlib.import_module(d["module"])
File "d:\programdata\vnstudio\lib\importlib__init.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
File "<frozen importlib._bootstrap>", line 983, in _find_and_load
File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 728, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "d:\programdata\vnstudio\lib\site-packages\vnpy\app\cta_backtester\init__.py", line 5, in <module>
from .engine import BacktesterEngine, APP_NAME
File "d:\programdata\vnstudio\lib\site-packages\vnpy\app\cta_backtester\engine.py", line 25

import vnpy.app.cta_strategy.base import EngineType     # hxxjava add
                                       ^

SyntaxError: invalid syntax

请问：B站交易系统，min(bar.low_price, self.lowest)，这个取得最低价，100个周期内的吗，还是开仓以后的。怎么加个时间限制呢？

elif self.pos < 0:

    # 持有空单的最低价记录

 ...