public function __construct($shell, $params = [])
 {
     parent::__construct($params);
     if ($shell instanceof Shell) {
         $this->shell = $shell;
     } else {
         $this->shell = new Shell();
     }
 }
 public function __get($key)
 {
     $result = parent::__get($key);
     if (!is_null($result)) {
         return $result;
     }
     $matched = [];
     if (preg_match('/^short_([0-9a-z_-]*_id)$/', $key, $matched) && isset($this->params[$matched[1]])) {
         return substr($this->params[$matched[1]], 0, static::DOCKER_SHORT_ID_LENGTH);
     }
     return null;
 }