Traceback (most recent call last):


 ".\test.py", line 24, in <module>

main().main_loop()


 "C:\Program 
s\Python37\lib\site-packages\toga_winforms\app.py", line 49, in main_loop

self._startup()


 "C:\Program 
s\Python37\lib\site-packages\toga_winforms\app.py", line 41, in _startup

self.startup()


 "C:\Program 
s\Python37\lib\site-packages\toga\interface\app.py", line 144, in startup

self.main_window.content = self._startup_method(self)


 ".\test.py", line 9, in build

box = toga.Box()


 "C:\Program 
s\Python37\lib\site-packages\toga_winforms\widgets\box.py", line 10, in __init__

super().__init__(id=id, style=style, children=children)


 "C:\Program 
s\Python37\lib\site-packages\toga\interface\widgets\box.py", line 21, in __init__

super().__init__(id=id, style=style, children=children)


 "C:\Program 
s\Python37\lib\site-packages\toga\interface\widgets\base.py", line 144, in __init__

self.style = CSS()


 "C:\Program 
s\Python37\lib\site-packages\toga\interface\widgets\base.py", line 170, in style

self._style = value.bind(self)
AttributeError: 'CSS' object has no attribute 'bind'

Traceback (most recent call last):

 "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/atexit.py", line 24, in _run_exitfuncs
func(*targs, **kargs)

 "/Users/zhenweigui/.dev/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 3206, in atexit_operations
self.reset(new_session=False)

 "/Users/zhenweigui/.dev/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 1200, in reset
self.history_manager.reset(new_session)

 "/Users/zhenweigui/.dev/lib/python2.7/site-packages/IPython/core/history.py", line 539, in reset
self.dir_hist[:] = [py3compat.getcwd()]OSError: [Errno 2] No such file or directory