public function save($filename, $overwrite = false)
    {

        if ($this->html)
        {
            $this->snappy->generateFromHtml($this->html, $filename, $this->options, $overwrite);
        }
        elseif ($this->file)
        {
            $this->snappy->generate($this->file, $filename, $this->options, $overwrite);
        }

        return $this;
    }