CTA策略，准备实盘操作。结果报错。重新安装也是同样的问题。请问如何解决
Traceback (most recent call last):
File "c:\vnstudio\lib\site-packages\vnpy\trader\ui\mainwindow.py", line 282, in open_widget
widget = widget_class(self.main_engine, self.event_engine)
File "c:\vnstudio\lib\site-packages\vnpy_ctastrategy\ui\widget.py", line 38, in init
self.cta_engine.init_engine()
File "c:\vnstudio\lib\site-packages\vnpy_ctastrategy\engine.py", line 115, in init_engine
self.load_strategy_data()
File "c:\vnstudio\lib\site-packages\vnpy_ctastrategy\engine.py", line 834, in load_strategy_data
self.strategy_data = load_json(self.data_filename)
File "c:\vnstudio\lib\site-packages\vnpy\trader\utility.py", line 99, in load_json
data = json.load(f)
File "c:\vnstudio\lib\json__init.py", line 296, in load
parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
File "c:\vnstudio\lib\json\init__.py", line 348, in loads
return _default_decoder.decode(s)
File "c:\vnstudio\lib\json\decoder.py", line 337, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "c:\vnstudio\lib\json\decoder.py", line 355, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 4 column 17 (char 57)
