code: public function execute()
      {
          try {
              if ($this->config->getType() == Config::FASTLY && $this->config->isEnabled()) {
                  // check if store exists
                  $storeId = $this->getRequest()->getParam('stores', false);
                  /** @var \Magento\Store\Model\Store $store */
                  $store = $this->storeManager->getStore($storeId);
                  if (!$store->getId()) {
                      throw new LocalizedException(__('Invalid store "'.$storeId.'" given.'));
                  }
  
                  $result = $this->purgeCache->sendPurgeRequest($store->getIdentities());
  
                  if ($result) {
                      $this->getMessageManager()->addSuccessMessage(__('The Fastly CDN has been cleaned.'));
                  } else {
                      $this->getMessageManager()->addErrorMessage(
                          __('The purge request was not processed successfully.')
                      );
                  }
              }
          } catch (\Exception $e) {
              $this->getMessageManager()->addErrorMessage(
                  __('An error occurred while clearing the Fastly CDN: ') . $e->getMessage()
              );
          }
          return $this->_redirect('*/cache/index');
      }
docs: Purge by content type
  
  @return \Magento\Framework\App\ResponseInterface
  @throws \Exception