private function getFiles(NodeInterface $node, string $field): array {
    $files = [];
    foreach ($node->get($field)->getValue() as $value) {
      $file = $this->entityTypeManager
        ->getStorage('file')
        ->load($value['target_id']);
      if ($file) {
        $url = $this->fileUrlGenerator
          ->generateAbsoluteString($file->getFileUri());
        $files[] = array("url" => $url);
      }
    }
    return $files;
  }