diff --git a/Include/funcobject.h b/Include/funcobject.h
index 59c19bb..3e37e11 100644
--- a/Include/funcobject.h
+++ b/Include/funcobject.h
@@ -39,7 +39,7 @@
 
 PyAPI_DATA(PyTypeObject) PyFunction_Type;
 
-#define PyFunction_Check(op) ((op)->ob_type == &PyFunction_Type)
+#define PyFunction_Check(op) (Py_Type(op) == &PyFunction_Type)
 
 PyAPI_FUNC(PyObject *) PyFunction_New(PyObject *, PyObject *);
 PyAPI_FUNC(PyObject *) PyFunction_GetCode(PyObject *);