Unexpected key argument 'priority'

I recently updated my jupyter book version and tried building a book and got the following error:

Exception occurred:
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/sphinx_external_toc/__init__.py", line 29, in setup
    app.connect("config-inited", parse_toc_to_env, priority=900)
TypeError: connect() got an unexpected keyword argument 'priority'
The full traceback has been saved in /tmp/sphinx-err-ttnt2_i9.log, if you want to report the issue to the developers.
Please also report this if it was a user error, so that a better error message can be provided next time.
A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!
Traceback (most recent call last):
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/jupyter_book/sphinx.py", line 128, in build_sphinx
    keep_going=keep_going,
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/sphinx/application.py", line 235, in __init__
    self.setup_extension(extension)
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/sphinx/application.py", line 394, in setup_extension
    self.registry.load_extension(self, extname)
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/sphinx/registry.py", line 484, in load_extension
    metadata = mod.setup(app)
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/sphinx_external_toc/__init__.py", line 29, in setup
    app.connect("config-inited", parse_toc_to_env, priority=900)
TypeError: connect() got an unexpected keyword argument 'priority'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/tomas/anaconda3/envs/pisco/bin/jupyter-book", line 8, in <module>
    sys.exit(main())
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/click/core.py", line 1137, in __call__
    return self.main(*args, **kwargs)
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/click/core.py", line 1062, in main
    rv = self.invoke(ctx)
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/click/core.py", line 1668, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/click/core.py", line 763, in invoke
    return __callback(*args, **kwargs)
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/jupyter_book/cli/main.py", line 317, in build
    result, builder, OUTPUT_PATH, build_type, PAGE_NAME, click.echo
  File "/home/tomas/anaconda3/envs/pisco/lib/python3.6/site-packages/jupyter_book/cli/main.py", line 516, in builder_specific_actions
    raise RuntimeError(_message_box(msg, color="red", doprint=False)) from result
RuntimeError: 
===============================================================================

There was an error in building your book. Look above for the cause.

===============================================================================

Any idea what could be causing this?

[temuller]

yeah, the issue was the version of packages. I had to update them for the build to work (see chrisjsewell’s comment above).

[choldgraf]

Sounds good - I’m gonna close this one since I think it was resolved by updating the environment. Let me know if there’s still something to tackle