diff --git a/Include/setobject.h b/Include/setobject.h
index 8914749..5b97fcb 100644
--- a/Include/setobject.h
+++ b/Include/setobject.h
@@ -58,6 +58,7 @@
 
 PyAPI_DATA(PyTypeObject) PySet_Type;
 PyAPI_DATA(PyTypeObject) PyFrozenSet_Type;
+PyAPI_DATA(PyTypeObject) PySetIter_Type;
 
 /* Invariants for frozensets:
  *     data is immutable.