diff --git a/main.py b/main.py
index 0b7b426..f3b3b24 100755
--- a/main.py
+++ b/main.py
@@ -47,13 +47,13 @@ def parse_args(args=sys.argv[1:]):  # pylint: disable=W0102
         "-f",
         "--foo",
         action="store_true",
-        default=False,
         dest="foo",
         help="Using foo",
     )
     group.add_argument(
         "-b",
         "--bar",
+        const="BAR",
         help="Using bar",
         metavar="BAR",
         nargs="?",