postfix: yolo try to see why my merge is not working

site-modules/profile/manifests/postfix/satellite.pp

@@ -28,10 +28,12 @@ class profile::postfix::satellite(
       'virtual_alias_maps'                      => 'hash:/etc/postfix/virtual',
     }
   } else {
-    $extra_params = {}
+    $extra_params = {
+      'foo' => 'bar',
+    }
   }
   class { 'profile::postfix':
-    extra_parameters    => deep_merge($params, $extra_params),
+    extra_parameters => $params + $extra_params,
   }
   postfix::config::service { 'smtptlsc':
     master_cf_file => '/etc/postfix/master.cf',