diff --git a/Objects/setobject.c b/Objects/setobject.c
index 9447441..aaa4838 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1978,6 +1978,8 @@
 
 	if (!PyAnySet_Check(self))
 		return -1;
+	if (PySet_Check(self) && !_PyArg_NoKeywords("set()", kwds))
+		return -1;
 	if (!PyArg_UnpackTuple(args, Py_TYPE(self)->tp_name, 0, 1, &iterable))
 		return -1;
 	set_clear_internal(self);