code: public function handleRoot(GetPasteRootButtonEvent $event)
      {
          $this->environment  = $event->getEnvironment();
          $this->provider     = $this->environment->getDataProvider();
          $this->providerName = $this->provider->getEmptyModel()->getProviderName();
          $clipboard          = $this->environment->getClipboard();
          $this->currentModel = null;
          $this->disablePI    = false;
  
          // Only run for a MetaModels.
          if ((substr($this->providerName, 0, 3) !== 'mm_') || $event->isPasteDisabled()) {
              return;
          }
  
          $this->checkForAction($clipboard, 'copy');
          $this->checkForAction($clipboard, 'create');
          $this->checkForAction($clipboard, 'cut');
  
          $event->setPasteDisabled($this->disablePI);
      }
docs: Handle the paste into and after buttons.
  
  @param GetPasteRootButtonEvent $event The event.
  
  @return void
  
  @throws \RuntimeException When more than one model is contained within the clipboard.