diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index ed513a7..e6099f8 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -10,7 +10,7 @@ class Configuration implements ConfigurationInterface
     /**
      * {@inheritdoc}
      */
-    public function getConfigTreeBuilder()
+    public function getConfigTreeBuilder(): TreeBuilder
     {
         
         $tb = new TreeBuilder('enqueue_elastica');