Warning on html_add_permalinks

[muhuk]

I'm getting this warning:

WARNING: the config value 'html_add_permalinks' has type `NoneType', defaults to `unicode.'

Using:

$ pip freeze
Babel==1.3
Jinja2==2.7.3
MarkupSafe==0.23
Pygments==2.0.2
Sphinx==1.3.1
Tinkerer==1.5
alabaster==0.7.6
argparse==1.2.1
cssselect==0.9.1
docutils==0.12
lxml==3.4.4
pyquery==1.2.9
pytz==2014.7
six==1.9.0
snowballstemmer==1.2.0
sphinx-rtd-theme==0.1.8
wsgiref==0.1.2

In my conf.py:

# **************************************************************
# Do not modify below lines as the values are required by
# Tinkerer to play nice with Sphinx
# **************************************************************

source_suffix = tinkerer.source_suffix
master_doc = tinkerer.master_doc
version = tinkerer.__version__
release = tinkerer.__version__
html_title = project
html_use_index = False
html_show_sourcelink = False
html_add_permalinks = None

Should I remove it from the config?

[muhuk]

Changing it as html_add_permalinks = '' seems to solve the issue.