diff --git a/Doc/extending/newtypes_tutorial.rst b/Doc/extending/newtypes_tutorial.rst
index ac48637bbee..07c2ef718ae 100644
--- a/Doc/extending/newtypes_tutorial.rst
+++ b/Doc/extending/newtypes_tutorial.rst
@@ -92,6 +92,7 @@ The second bit is the definition of the type object. ::
        .tp_doc = "Custom objects",
        .tp_basicsize = sizeof(CustomObject),
        .tp_itemsize = 0,
+       .tp_flags = Py_TPFLAGS_DEFAULT,
        .tp_new = PyType_GenericNew,
    };