code: public function getClassProperties()
      {
          return [
              'type' => $this->getType(),
              'number' => $this->getNumber(),
              'email' => $this->getEmail(),
              'newsletter' => $this->getNewsletter(),
              'newsletterAgreementDate' => $this->getNewsletterAgreementDate(),
              'languageIdentifier' => $this->getLanguageIdentifier(),
              'customerGroupIdentifier' => $this->getCustomerGroupIdentifier(),
              'gender' => $this->getGender(),
              'title' => $this->getTitle(),
              'firstname' => $this->getFirstname(),
              'lastname' => $this->getLastname(),
              'birthday' => $this->getBirthday(),
              'phoneNumber' => $this->getPhoneNumber(),
              'mobilePhoneNumber' => $this->getMobilePhoneNumber(),
              'shopIdentifier' => $this->getShopIdentifier(),
          ];
      }
docs: {@inheritdoc}