code: public function getClassProperties()
      {
          return [
              'type' => $this->getType(),
              'quantity' => $this->getQuantity(),
              'name' => $this->getName(),
              'number' => $this->getNumber(),
              'price' => $this->getPrice(),
              'vatRateIdentifier' => $this->getVatRateIdentifier(),
              'attributes' => $this->getAttributes(),
          ];
      }
docs: {@inheritdoc}