'NoneType' object has no attribute 'filename' when building bokeh doc


I follow the documentation section of dev guide to build bokeh doc, but got the following error. I do make some changes on doc, but the error message here doesn’t convey much useful information to me. Does anyone know what might be wrong ? Thanks

/Users/jzhang/github/bokeh/bokeh/core/compat/mplexporter/exporter.py:176: UserWarning: Legend element <matplotlib.offsetbox.HPacker object at 0x122a933c8> nd

warnings.warn(“Legend element %s not implemented” % child)

copying gallery files… [100%] seaborn_sinerror.py

copying bokeh-plot files… [100%] bokeh-plot-ff7edabe052448ba50e8fd7ac647ccaa.js

Exception occurred:

File “/Users/jzhang/github/bokeh/bokeh/sphinxext/bokeh_jinja.py”, line 48, in run

template_text = open(template.filename).read()

AttributeError: ‘NoneType’ object has no attribute ‘filename’

The full traceback has been saved in /var/folders/dp/hmchg5dd3vbcvds26q91spdw0000gp/T/sphinx-err-0708wvl6.log, if you want to report the issue to the develo.

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!

make: *** [html] Error 1