vs = $vs;
  }
  protected $vs;
  function printError(): void {
    $error = $this->getError();
    $message = $error["message"];
    if (!$message) $message = $this->vs;
    if (!$message) $message = "Une erreur inattendue s'est produite";
    vo::p(["class" => "error-message", q($message)]);
    $exception = $error["exception"];
    if ($exception) {
      vo::pre(["class" => "error-exception",
        q(UserException::get_summary($exception)), "\n",
        q(UserException::get_traceback($exception)),
      ]);
    }
  }
  function print(): void {
    page::no_cache();
    http::error500(null, null, false);
    $this->printError();
  }
}