protected function storeStructuredHeader(): bool
    {
        if (is_null($this->structuredHeaders)) {
            return false;
        }
        $headers = array("");

        foreach ($this->structuredHeaders as $h) {
            $headers[] = $h['key'] . ': ' . $h['value'] . "\n";
        }
        $this->entry[PoTokens::TRANSLATED] = $headers;
        return true;
    }