code: protected function process($table, $metaModelName, $parentId, Request $request)
      {
          $this->knownAttributes = $this->fetchExisting($table, $parentId);
  
          $metaModel = $this->factory->getMetaModel($metaModelName);
          if (!$metaModel) {
              throw new \RuntimeException('Could not retrieve MetaModel ' . $metaModelName);
          }
          if ($request->request->has('add') || $request->request->has('saveNclose')) {
              $this->perform($table, $request, $metaModel, $parentId);
              // If we want to close, go back to referer.
              if ($request->request->has('saveNclose')) {
                  return new RedirectResponse($this->getReferer($request, $table, false));
              }
          }
  
          return new Response($this->templating->render(
              'MetaModelsCoreBundle::Backend/add-all.html.twig',
              $this->render($table, $metaModel, $request)
          ));
      }
docs: Process the request.
  
  @param string  $table         The table name.
  @param string  $metaModelName The MetaModel name.
  @param string  $parentId      The parent id.
  @param Request $request       The request.
  
  @return Response
  
  @throws \RuntimeException Throws if could not retrieve a metamodel.