diff -r 6bcedf96d25f Objects/dictobject.c
--- a/Objects/dictobject.c	Tue Sep 13 20:48:25 2016 +0200
+++ b/Objects/dictobject.c	Wed Sep 14 17:35:01 2016 +0800
@@ -420,7 +420,7 @@
  * (which cannot fail and thus can do no allocation).
  */
 static PyDictKeysObject empty_keys_struct = {
-        2, /* dk_refcnt 1 for this struct, 1 for dummy_struct */
+        1, /* dk_refcnt */
         1, /* dk_size */
         lookdict_split, /* dk_lookup */
         0, /* dk_usable (immutable) */