this is only a borrowed ref in Brett's branch
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 0651d1d..9daa12a 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -2126,7 +2126,7 @@
             Py_DECREF(args_tuple);
         }
     }
-
+    Py_DECREF(bltinmod);
 }
 
 void