diff --git a/gn_helper.py b/gn_helper.py
index 440d8be7ee..1bb9c9ae35 100644
--- a/gn_helper.py
+++ b/gn_helper.py
@@ -5,6 +5,7 @@
 
 import os
 import re
+import sys
 
 
 def _find_root(output_dir):