diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index e034f15..b9d9dfd 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -9,11 +9,13 @@
  * This is the class that validates and merges configuration from your app/config files
  *
  * To learn more see {@link http://symfony.com/doc/current/cookbook/bundles/extension.html#cookbook-bundles-extension-config-class}
+ *
+ * @final
  */
 class Configuration implements ConfigurationInterface
 {
     /**
-     * {@inheritDoc}
+     * @return TreeBuilder
      */
     public function getConfigTreeBuilder()
     {
diff --git a/TwigExtension.php b/TwigExtension.php
index 98b1531..af1ee90 100644
--- a/TwigExtension.php
+++ b/TwigExtension.php
@@ -6,6 +6,9 @@
 use Twig\Extension\AbstractExtension;
 use Twig\TwigFunction;
 
+/**
+ * @final
+ */
 class TwigExtension extends AbstractExtension
 {
     private $router;
@@ -18,6 +21,9 @@ public function __construct(UrlGeneratorInterface $router, $stackTracePath = nul
         $this->stackTracePath = $stackTracePath;
     }
 
+    /**
+     * @return array
+     */
     public function getFunctions()
     {
         return array(