Use identifier API for PyObject_GetAttrString.
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 34d8204..8f6325a 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1933,6 +1933,7 @@
 set_reduce(PySetObject *so)
 {
     PyObject *keys=NULL, *args=NULL, *result=NULL, *dict=NULL;
+    _Py_identifier(__dict__);
 
     keys = PySequence_List((PyObject *)so);
     if (keys == NULL)
@@ -1940,7 +1941,7 @@
     args = PyTuple_Pack(1, keys);
     if (args == NULL)
         goto done;
-    dict = PyObject_GetAttrString((PyObject *)so, "__dict__");
+    dict = _PyObject_GetAttrId((PyObject *)so, &PyId___dict__);
     if (dict == NULL) {
         PyErr_Clear();
         dict = Py_None;