public function addXmlAcceptanceCertificateSellerTitles(\AgentSIB\Diadoc\Api\Proto\Events\XmlDocumentAttachment $value)
    {
        if ($this->XmlAcceptanceCertificateSellerTitles === null) {
            $this->XmlAcceptanceCertificateSellerTitles = new \Protobuf\MessageCollection();
        }

        $this->XmlAcceptanceCertificateSellerTitles->add($value);
    }