如何使用 jupyter 笔记本解决 travis 上的 sphinx 错误？

如何解决如何使用 jupyter 笔记本解决 travis 上的 sphinx 错误？

我在 github (https://github.com/environmentalscience/essm/pull/101) 上有一个 PR，其中 travis-ci 给出了以下错误消息 (https://travis-ci.com/github/schymans/essm/builds/232006356)：

reading sources... [ 40%] examples/api_features                                 

Exception occurred:

  File "/home/travis/virtualenv/python3.6.7/lib/python3.6/site-packages/nbsphinx.py",line 1813,in apply

    env.get_domain('math').data['has_equations'][env.docname] = True

KeyError: 'has_equations'

The full traceback has been saved in /tmp/sphinx-err-0rei5dw_.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!

The command "python setup.py build_sphinx" exited with 1.

examples/api_features.ipynb 是一个 jupyter notebook，所以它与通过 sphinx 渲染 jupyter notebooks 有关系，但是相同的命令 (python setup.py build_sphinx) 在我的本地计算机上运行得很好，我没有改变此文件自上次成功构建 travis 以来，因此我不知道如何解决此问题，因为我无法访问 travis-ci 上的 /tmp/。有人知道我应该尝试什么吗？