diff --git a/make_graph.py b/make_graph.py
index 429125e..f33e2b5 100755
--- a/make_graph.py
+++ b/make_graph.py
@@ -2,7 +2,7 @@
 # SPDX-FileCopyrightText: Eric S. Raymond <esr@thyrsus.com>
 # SPDX-License-Identifier: BSD-2-Clause
 """\
-usage: make_graph.py [-a] -d] [-m] [-s]
+usage: make_graph.py [-a] -d] [-m] [-s] [-v]
 
 Make a DOT graph of Colossal Cave.