diff -r 8bc711bdd180 -r 0f66e8a1364a lib/Exim/Grey.pm
--- a/lib/Exim/Grey.pm	Thu Jun 02 22:17:27 2016 +0200
+++ b/lib/Exim/Grey.pm	Sat Jun 04 22:07:30 2016 +0200
@@ -6,7 +6,7 @@
 use base 'Exporter';
 use Carp;
 
-our @EXPORT_OK   = qw(unseen getDBDir connectDB getDefault);
+our @EXPORT_OK   = qw(unseen seen getDBDir connectDB getDefault);
 our %EXPORT_TAGS = (all => \@EXPORT_OK,);
 our $VERSION     = '2.0';
 
@@ -70,6 +70,10 @@
     return 'no';
 }
 
+sub seen {
+    return(unseen(@_) eq 'yes' ? 'no' : 'yes');
+}
+
 # According to a thought from "David Woodhouse <dwmw2@infradead.org>"
 # on exim-users@exim.org (Thu, 08 May 2008 13:10:21 +0100,
 # Message-Id: <1210248621.25560.1088.camel@pmac.infradead.org>) we