Revert r86726.  Sorry about interfering with the rc.
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 56f3087..00cabe6 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1858,7 +1858,7 @@
         tmpkey = make_new_set(&PyFrozenSet_Type, key);
         if (tmpkey == NULL)
             return -1;
-        rv = set_contains_key(so, tmpkey);
+        rv = set_contains(so, tmpkey);
         Py_DECREF(tmpkey);
     }
     return rv;