diff --git a/Objects/classobject.c b/Objects/classobject.c
index 3dc23b7..095b0ca 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -73,7 +73,7 @@
 }
 
 static PyObject *
-method_reduce(PyMethodObject *im)
+method_reduce(PyMethodObject *im, PyObject *Py_UNUSED(ignored))
 {
     PyObject *self = PyMethod_GET_SELF(im);
     PyObject *func = PyMethod_GET_FUNCTION(im);