diff --git a/commands/core/outputformat/yaml.inc b/commands/core/outputformat/yaml.inc
index 51fd908..0709da2 100644
--- a/commands/core/outputformat/yaml.inc
+++ b/commands/core/outputformat/yaml.inc
@@ -100,4 +100,5 @@ function drush_environment_yaml_lib() {
   }
   $success = TRUE;
   require_once $file;
+  return $success;
 }