public function create()
    {
        $params = array(
            'start' => $this->getStart(),
            'hash' => $this->getHash(),
            'parameters' => implode(',', $this->getParameters())
        );
        if (is_int($this->end)) {
            $params['end'] = $this->getEnd();
        }
        $this->fromResponse($this->getUser()->post('preview/create', $params));
    }