diff --git a/OptionsResolver.php b/OptionsResolver.php
index d4e247b..6c6764e 100644
--- a/OptionsResolver.php
+++ b/OptionsResolver.php
@@ -1084,6 +1084,8 @@ public function offsetExists($option)
     /**
      * Not supported.
      *
+     * @return void
+     *
      * @throws AccessException
      */
     public function offsetSet($option, $value)
@@ -1094,6 +1096,8 @@ public function offsetSet($option, $value)
     /**
      * Not supported.
      *
+     * @return void
+     *
      * @throws AccessException
      */
     public function offsetUnset($option)