public function perform(DataBackend $backend)
    {
        $isNotice = $this->notice;
        $lock = new Lock(self::UPDATE_LOCK);
        $lock->nonblockingExecuteOnce(
            function () use ($backend, $isNotice) {
                $backend->update();
                if ($isNotice) {
                    trigger_error("bav's bank data was updated sucessfully.", E_USER_NOTICE);

                }
            }
        );
    }