code: public function init()
      {
          parent::init();
  
          $this->identityElement = $this->getFormFactory()->getFormElementManager()->get('CmsAuthenticationIdentity');
  
          $this->add(
              $this->identityElement,
              ['priority' => 20]
          );
  
          $this->add(
              ['type'  => 'CmsUserBirthdayVerify'],
              ['priority' => 10]
          );
  
          $this->getEventManager()->trigger(__FUNCTION__ . '.post', $this);
      }
docs: {@inheritDoc}