+__PACKAGE__->configure_acts_as_list(group_by => [qw(trans_id)]);
+
+__PACKAGE__->meta->add_relationships(
+  invoice          => {
+    type           => 'one to one',
+    class          => 'SL::DB::Invoice',
+    column_map     => { trans_id => 'id' },
+  },
+
+  purchase_invoice => {
+    type           => 'one to one',
+    class          => 'SL::DB::PurchaseInvoice',
+    column_map     => { trans_id => 'id' },
+  },
+);
+