public function metrics($id, $filter, $start, $end){
        $param = array(
            'start' => date("Y-m-d\TH:i:s\Z", $start),
            'end' => date("Y-m-d\TH:i:s\Z", $end),
            'filter' => $filter
        );

        $param = $this->makeJsonReady($param);

        return $this->get('metrics/graphs/'.urlencode($id), $param);
    }