public static function remove_user_role($username, $id, $roleid)
 {
     global $CFG, $DB;
     $params = self::validate_parameters(self::remove_user_role_parameters(), array('username' => $username, 'id' => $id, 'roleid' => $roleid));
     $auth = new auth_plugin_joomdle();
     $id = $auth->remove_user_role($username, $id, $roleid);
     return $id;
 }