public function getPartByContentId($contentId)
    {
        $sanitized = preg_replace('/^\s*<|>\s*$/', '', $contentId);
        $filter = $this->partFilterFactory->newFilterFromArray([
            'headers' => [
                PartFilter::FILTER_INCLUDE => [
                    'Content-ID' => $sanitized
                ]
            ]
        ]);
        return $this->getPart(0, $filter);
    }