diff --git a/subcmds/prune.py b/subcmds/prune.py
index 39c571a..dc8b8c9 100644
--- a/subcmds/prune.py
+++ b/subcmds/prune.py
@@ -1,3 +1,4 @@
+# -*- coding:utf-8 -*-
 #
 # Copyright (C) 2008 The Android Open Source Project
 #