▶ jupyter nbextension enable toc2/main
Enabling notebook extension toc2/main...
Traceback (most recent call last):
  File "/home/pauperei/.conda/envs/py36/bin/jupyter-nbextension", line 11, in <module>
    sys.exit(main())
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/jupyter_core/application.py", line 267, in launch_instance
    return super(JupyterApp, cls).launch_instance(argv=argv, **kwargs)
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/traitlets/config/application.py", line 658, in launch_instance
    app.start()
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/notebook/nbextensions.py", line 900, in start
    super(NBExtensionApp, self).start()
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/jupyter_core/application.py", line 256, in start
    self.subapp.start()
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/notebook/nbextensions.py", line 810, in start
    self.toggle_nbextension(self.extra_args[0])
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/notebook/nbextensions.py", line 800, in toggle_nbextension
    logger=self.log)
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/notebook/nbextensions.py", line 393, in enable_nbextension
    logger=logger)
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/notebook/nbextensions.py", line 331, in _set_nbextension_state
    cm.update(section, {"load_extensions": {require: state}})
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/traitlets/config/manager.py", line 85, in update
    data = self.get(section_name)
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/site-packages/traitlets/config/manager.py", line 63, in get
    return json.load(f)
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/json/__init__.py", line 299, in load
    parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/json/__init__.py", line 354, in loads
    return _default_decoder.decode(s)
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/json/decoder.py", line 339, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/home/pauperei/.conda/envs/py36/lib/python3.6/json/decoder.py", line 355, in raw_decode
    obj, end = self.scan_once(s, idx)
json.decoder.JSONDecodeError: Expecting property name enclosed in double quotes: line 5 column 3 (char 133)