diff --git a/lib/registry.js b/lib/registry.js
index f6d53719..7757022e 100644
--- a/lib/registry.js
+++ b/lib/registry.js
@@ -227,8 +227,8 @@ Registry.prototype.configureModel = function(ModelCtor, config) {
   // configuration, so that the datasource picks up updated relations
   if (config.dataSource) {
     assert(config.dataSource instanceof DataSource,
-        g.f('Cannot configure %s: {{config.dataSource}} must be an instance ' +
-          'of {{DataSource}}', ModelCtor.modelName));
+        'Cannot configure ' + ModelCtor.modelName +
+        ': config.dataSource must be an instance of DataSource');
     ModelCtor.attachTo(config.dataSource);
     debug('Attached model `%s` to dataSource `%s`',
       modelName, config.dataSource.name);