diff --git a/reference/array/functions/array-keys.xml b/reference/array/functions/array-keys.xml
index b5c508cc21..84dcb70f70 100644
--- a/reference/array/functions/array-keys.xml
+++ b/reference/array/functions/array-keys.xml
@@ -11,7 +11,7 @@
   <methodsynopsis>
    <type>array</type><methodname>array_keys</methodname>
    <methodparam><type>array</type><parameter>array</parameter></methodparam>
-   <methodparam choice="opt"><type>mixed</type><parameter>search_value</parameter><initializer>&null;</initializer></methodparam>
+   <methodparam choice="opt"><type>mixed</type><parameter>search_value</parameter></methodparam>
    <methodparam choice="opt"><type>bool</type><parameter>strict</parameter><initializer>false</initializer></methodparam>
   </methodsynopsis>
   <para>