diff --git a/www-swagg.pl b/www-swagg.pl
index 0759c84..7182ea6 100755
--- a/www-swagg.pl
+++ b/www-swagg.pl
@@ -19,7 +19,7 @@ under sub {
     my ($c) = @_;
 
     if ($c->cookie('banner') eq 'seen') {
-        $c->session->{banner} = 'seen' unless $c->session->{banner}
+        $c->session->{banner} //= 'seen'
     }
 
     1;