public function export_headers()
    {
        $header_string = '';
        foreach ($this->headers as $header => $value) {
            $header_string .= "$header: $value\n";
        }
        $poified = self::poify($header_string);
        if ($this->comments_before_headers) {
            $before_headers = self::prepend_each_line(
                rtrim($this->comments_before_headers) . "\n",
                '# '
            );
        } else {
            $before_headers = '';
        }

        return rtrim("{$before_headers}msgid \"\"\nmsgstr $poified");
    }