Add missing return type
diff --git a/system/libraries/Xmlrpc.php b/system/libraries/Xmlrpc.php
index 9d7cbff..8fbc18f 100644
--- a/system/libraries/Xmlrpc.php
+++ b/system/libraries/Xmlrpc.php
@@ -1792,6 +1792,7 @@
 	 *
 	 * @param	string
 	 * @param	mixed
+	 * @return	string
 	 */
 	public function serializedata($typ, $val)
 	{