diff --git a/Include/abstract.h b/Include/abstract.h
index 46a6f54..0bbcee5 100644
--- a/Include/abstract.h
+++ b/Include/abstract.h
@@ -1273,6 +1273,11 @@
       /* issubclass(object, typeorclass) */
 
 
+PyAPI_FUNC(int) _PyObject_RealIsInstance(PyObject *inst, PyObject *cls);
+
+PyAPI_FUNC(int) _PyObject_RealIsSubclass(PyObject *derived, PyObject *cls);
+
+
 #ifdef __cplusplus
 }
 #endif