diff --git a/license-update.py b/license-update.py
index e97d215412..24e61a01aa 100755
--- a/license-update.py
+++ b/license-update.py
@@ -7,6 +7,7 @@
 from datetime import date
 import os
 import re
+import sys
 
 sep = os.sep
 # If directory separator is backslash, escape it for regexes