diff --git a/docs/source/index.rst b/docs/source/index.rst
index 4cf77d3f9db8be7ad33e539c24b8e42bb90a54c3..8c341654b39207b3e3fac1407b3271c65e660d2d 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -14,7 +14,7 @@ Contents
 ========
 
 .. toctree::
-   ::maxdepth: 2
+   :maxdepth: 2
 
    caesar
    aspis