diff --git a/module/dept/model.php b/module/dept/model.php
index fb551eeca6..2898370902 100644
--- a/module/dept/model.php
+++ b/module/dept/model.php
@@ -298,10 +298,11 @@ class deptModel extends model
      * Delete a department.
      * 
      * @param  int    $deptID 
+     * @param  null   $null      compatible with that of model::delete()
      * @access public
      * @return void
      */
-    public function delete($deptID)
+    public function delete($deptID, $null = null)
     {
         $this->dao->delete()->from(TABLE_DEPT)->where('id')->eq($deptID)->exec();
     }