win10,vnpy2.08,配置了ricequant数据接口，点主界面的功能--回测出现下面错误：

Traceback (most recent call last):
  File "Z:\vnpy_dev\vnpy\trader\ui\mainwindow.py", line 278, in open_widget
    widget = widget_class(self.main_engine, self.event_engine)
  File "Z:\vnpy_dev\vnpy\app\cta_backtester\ui\widget.py", line 43, in __init__
    self.backtester_engine.init_engine()
  File "Z:\vnpy_dev\vnpy\app\cta_backtester\engine.py", line 60, in init_engine
    self.init_rqdata()
  File "Z:\vnpy_dev\vnpy\app\cta_backtester\engine.py", line 66, in init_rqdata
    result = rqdata_client.init()
  File "Z:\vnpy_dev\vnpy\trader\rqdata.py", line 60, in init
    df = rqdata_all_instruments()
  File "C:\Anaconda3\envs\vnpy_dev\lib\site-packages\rqdatac\decorators.py", line 131, in wrap
    return func(*args, **kwargs)
  File "C:\Anaconda3\envs\vnpy_dev\lib\site-packages\rqdatac\services\basic.py", line 319, in all_instruments
    ins_ret = filter(cond, _all_instruments_list(market))
  File "C:\Anaconda3\envs\vnpy_dev\lib\site-packages\rqdatac\decorators.py", line 111, in wrapper
    value = user_function(*args, **kwargs)
  File "C:\Anaconda3\envs\vnpy_dev\lib\site-packages\rqdatac\services\basic.py", line 107, in _all_instruments_list
    return [Instrument(i) for i in get_client().execute("all_instruments", market)]
TypeError: 'NoneType' object is not iterable

已经解决了，mongo数据库连接参数设置错了。