diff --git a/docs/conf.py b/docs/conf.py
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -214,7 +214,7 @@
 #html_use_smartypants = True
 
 # Custom sidebar templates, maps document names to template names.
-html_sidebars = {'index': 'indexsidebar.html'}
+html_sidebars = {'index': ['indexsidebar.html']}
 
 # Additional templates that should be rendered to pages, maps page names to
 # template names.