/**
  * Cache the specific ignores to a file.
  *
  * @since 0.1.0
  *
  * @param string $file The full path of the file to write the cache to.
  *
  * @return bool Whether the cache was written successfully.
  */
 public function write_cache($file = '')
 {
     $ignores = $this->ignores;
     $cached_ignores = $this->old_ignores;
     if (empty($file)) {
         $file = parent::$config['ignores-cache'];
     } else {
         $cached_ignores = parent::load_json_file($file);
     }
     if (is_array($cached_ignores)) {
         $ignores = array_merge($cached_ignores, $ignores);
     }
     return parent::save_json_file($file, $ignores);
 }