diff --git a/doc/source/conf.py b/doc/source/conf.py
index 365a1b7086b..d3f486f19c5 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -25,7 +25,7 @@ import sys, os
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ['sphinx.ext.autodoc', 'sphinx.ext.todo', 'sphinx.ext.coverage', 'sphinx.ext.viewcode']
+extensions = ['sphinx.ext.autodoc', 'sphinx.ext.todo', 'sphinx.ext.coverage' ]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']