Incorporate some suggestions by Tait Stevens.
diff --git a/Doc/tutorial/classes.rst b/Doc/tutorial/classes.rst
index bca9108..43f2c6d 100644
--- a/Doc/tutorial/classes.rst
+++ b/Doc/tutorial/classes.rst
@@ -208,7 +208,7 @@
 definition looked like this::
 
    class MyClass:
-       "A simple example class"
+       """A simple example class"""
        i = 12345
        def f(self):
            return 'hello world'