diff --git a/model/DataList.php b/model/DataList.php
index c306c5f08..880da4c17 100644
--- a/model/DataList.php
+++ b/model/DataList.php
@@ -372,6 +372,8 @@ class DataList extends ViewableData implements SS_List, SS_Filterable, SS_Sortab
 
 	/**
 	 * Return a new instance of the list with an added filter
+	 *
+	 * @param array $filterArray
 	 */
 	public function addFilter($filterArray) {
 		$list = $this;