diff --git a/Include/setobject.h b/Include/setobject.h
index cea95cc..cc93968 100644
--- a/Include/setobject.h
+++ b/Include/setobject.h
@@ -78,10 +78,13 @@
 PyAPI_FUNC(PyObject *) PyFrozenSet_New(PyObject *);
 PyAPI_FUNC(Py_ssize_t) PySet_Size(PyObject *anyset);
 #define PySet_GET_SIZE(so) (((PySetObject *)(so))->used)
+PyAPI_FUNC(int) PySet_Clear(PyObject *set);
 PyAPI_FUNC(int) PySet_Contains(PyObject *anyset, PyObject *key);
 PyAPI_FUNC(int) PySet_Discard(PyObject *set, PyObject *key);
 PyAPI_FUNC(int) PySet_Add(PyObject *set, PyObject *key);
+PyAPI_FUNC(int) _PySet_Next(PyObject *set, Py_ssize_t *pos, PyObject **entry);
 PyAPI_FUNC(PyObject *) PySet_Pop(PyObject *set);
+PyAPI_FUNC(int) _PySet_Update(PyObject *set, PyObject *iterable);
 
 #ifdef __cplusplus
 }