diff --git a/import.py b/import.py
index b25e7cd..de50ee3 100755
--- a/import.py
+++ b/import.py
@@ -20,6 +20,7 @@
     parser.add_argument('-f', '--force', action='store_true',
                         help='Don\'t validate labels against the issues repo.')
     parser.add_argument('-o', '--origin', action='store_true',
+                        choices=['moz', 'ms', 'blink', 'apple'],
                         help='Adjust the import to the JSON issue format')
     parser.add_argument('-d', '--dry-run', action='store_true',
                         help='No modifications, just testing')