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

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