Use identifier API for PyObject_GetAttrString.
diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index 23ea2eb..d13b438 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -463,6 +463,7 @@
 {
     PyObject *readline = NULL, *stream = NULL, *io = NULL;
     _Py_identifier(open);
+    _Py_identifier(readline);
     int fd;
 
     io = PyImport_ImportModuleNoBlock("io");
@@ -481,7 +482,7 @@
         goto cleanup;
 
     Py_XDECREF(tok->decoding_readline);
-    readline = PyObject_GetAttrString(stream, "readline");
+    readline = _PyObject_GetAttrId(stream, &PyId_readline);
     tok->decoding_readline = readline;
 
     /* The file has been reopened; parsing will restart from