address review

Author: kumaraditya303

Objects/object.c

@@ -2794,6 +2794,9 @@ int
 PyUnstable_SetImmortal(PyObject *op)
 {
     assert(op != NULL);
+    if (!_PyObject_IsUniquelyReferenced(op) || PyUnicode_Check(op)) {
+        return 0;
+    }
     _Py_SetImmortal(op);
     return 1;
 }