public function stats_blast($blast_id = null, $start_date = null, $end_date = null, array $data = [ ]) {
        $data['stat'] = 'blast';
        if (!is_null($blast_id)) {
            $data['blast_id'] = $blast_id;
        }
        if (!is_null($start_date)) {
            $data['start_date'] = $start_date;
        }
        if (!is_null($end_date)) {
            $data['end_date'] = $end_date;
        }
        return $this->stats($data);
    }