diff --git a/Doc/tutorial/classes.rst b/Doc/tutorial/classes.rst
index 33171cd..b4f09c2 100644
--- a/Doc/tutorial/classes.rst
+++ b/Doc/tutorial/classes.rst
@@ -180,7 +180,9 @@
    scope_test()
    print("In global scope:", spam)
 
-The output of the example code is::
+The output of the example code is:
+
+.. code-block:: none
 
    After local assignment: test spam
    After nonlocal assignment: nonlocal spam