PyEval_CallObject requires a tuple of args (closes #13186)
diff --git a/Objects/classobject.c b/Objects/classobject.c
index 0832531..161906a 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -1221,7 +1221,7 @@
     if (func == NULL)
         return -1;
     if (item == NULL)
-        arg = PyInt_FromSsize_t(i);
+        arg = Py_BuildValue("(n)", i);
     else
         arg = Py_BuildValue("(nO)", i, item);
     if (arg == NULL) {