diff --git a/Include/dictobject.h b/Include/dictobject.h
index 853fd7f6e26..2b1974ba7eb 100644
--- a/Include/dictobject.h
+++ b/Include/dictobject.h
@@ -43,4 +43,5 @@ extern int getdictsize PROTO((object *dp));
 extern char *getdictkey PROTO((object *dp, int i));
 extern object *getdictkeys PROTO((object *dp));
 
+extern object *dict2key PROTO((object *dp, int i));
 extern int dict2insert PROTO((object *dp, object *key, object *item));