code: public function savereview($data, Form $form)
      {
          $page = $this->findRecord($data);
  
          $results = $this->getReviewContentHandler()->submitReview($page, $data);
          if (is_null($results)) {
              return null;
          }
          if ($this->getSchemaRequested()) {
              // Send extra "message" data with schema response
              $extraData = ['message' => $results];
              $schemaId = $this->owner->join_links($this->owner->Link('schema/ReviewContentForm'), $page->ID);
              return $this->getSchemaResponse($schemaId, $form, null, $extraData);
          }
  
          return $results;
      }
docs: Action handler for processing the submitted content review
  
  @param array $data
  @param Form $form
  @return DBHTMLText|HTTPResponse|null