diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index ea46a44..5116404 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -14617,7 +14617,7 @@
     /* make sure number is a type of integer for o, x, and X */
     if (!PyLong_Check(v)) {
         if (type == 'o' || type == 'x' || type == 'X') {
-            iobj = PyNumber_Index(v);
+            iobj = _PyNumber_Index(v);
             if (iobj == NULL) {
                 if (PyErr_ExceptionMatches(PyExc_TypeError))
                     goto wrongtype;