diff --git a/pep-0422.txt b/pep-0422.txt
--- a/pep-0422.txt
+++ b/pep-0422.txt
@@ -133,6 +133,11 @@
 ``super()`` works as expected, since the ``__class__`` reference is already
 initialised.
 
+To support cooperative multiple inheritance of the class initialisation hook,
+``object`` will have an ``__init_class__`` method (which will do nothing). As
+a consequence, it will be safe to call ``super().__init_class__()`` without
+checking if it exists.
+
 This general proposal is not a new idea (it was first suggested for
 inclusion in the language definition `more than 10 years ago`_, and a
 similar mechanism has long been supported by `Zope's ExtensionClass`_),
@@ -290,12 +295,7 @@
        @classmethod
        def __init_class__(cls):
            # Process any classes later in the MRO
-           try:
-               mro_chain = super().__init_class__
-           except AttributeError:
-               pass
-           else:
-               mro_chain()
+           super().__init_class__()
            # Process any __decorators__ attributes in the MRO
            for entry in reversed(cls.mro()):
                decorators = entry.__dict__.get("__decorators__", ())