diff -r 572bb8c265c0 Objects/typeobject.c
--- a/Objects/typeobject.c	Sun Jan 29 18:36:34 2012 +0100
+++ b/Objects/typeobject.c	Sun Jan 29 22:04:30 2012 +0100
@@ -2385,6 +2385,9 @@
         }
     }
 
+    if (PyType_Ready((PyTypeObject *)res) < 0)
+        goto fail;
+
     return (PyObject*)res;
 
  fail: