Traceback (most recent call last):


 "<stdin>", line 1, in <module>


 "/usr/local/lib/python3.7/dist-packages/toga_gtk/widgets/webview.py", line 24, in __init__

super().__init__(id=id, style=style, url=url, on_key_down=on_key_down)


 "/usr/local/lib/python3.7/dist-packages/toga/interface/widgets/webview.py", line 29, in __init__

super(WebView, self).__init__(id=id, style=style, url=url, on_key_down=on_key_down, on_webview_load=None)


 "/usr/local/lib/python3.7/dist-packages/toga/interface/widgets/base.py", line 144, in __init__

self.style = CSS()


 "/usr/local/lib/python3.7/dist-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):


 "/home/jin/habitat/habitat-lab/habitat/core/vector_env.py", line 563, in __del__


 "/home/jin/habitat/habitat-lab/habitat/core/vector_env.py", line 429, in close


 "/home/jin/anaconda3/envs/habitat7/lib/python3.6/multiprocessing/connection.py", line 206, in send
AttributeError: 'NoneType' object has no attribute 'dumps'
