diff --git a/Include/object.h b/Include/object.h
index fbeb915..46f4ce6 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -171,6 +171,7 @@
 	unaryfunc nb_int;
 	unaryfunc nb_long;
 	unaryfunc nb_float;
+	/* NB: nb_oct and nb_hex are not used anymore. */
 	unaryfunc nb_oct;
 	unaryfunc nb_hex;