diff --git a/Form/Type/KeyValueType.php b/Form/Type/KeyValueType.php
index 0f5c13a..ddd6e2d 100644
--- a/Form/Type/KeyValueType.php
+++ b/Form/Type/KeyValueType.php
@@ -71,7 +71,7 @@ public function configureOptions(OptionsResolver $resolver)
 
         if (method_exists($resolver, 'setDefined')) {
             // Symfony 2.6+ API
-            $resolver->setAllowedTypes('allowed_keys' => array('null', 'array'));
+            $resolver->setAllowedTypes(array('allowed_keys' => array('null', 'array')));
         } else {
             // Symfony <2.6 API
             $resolver->setAllowedTypes(array('allowed_keys' => array('null', 'array')));