code: public function advanceReviewDate()
      {
          $nextDateTimestamp = false;
          $options = $this->getOptions();
  
          if ($options && $options->ReviewPeriodDays) {
              $nextDateTimestamp = strtotime(
                  ' + ' . $options->ReviewPeriodDays . ' days',
                  DBDatetime::now()->getTimestamp()
              );
  
              $this->owner->NextReviewDate = DBDate::create()->setValue($nextDateTimestamp)->Format(DBDate::ISO_DATE);
              $this->owner->write();
          }
  
          return (bool)$nextDateTimestamp;
      }
docs: Advance review date to the next date based on review period or set it to null
  if there is no schedule. Returns true if date was required and false is content
  review is 'off'.
  
  @return bool