public function isPaid()
    {
        $response = array_get($this->data, 'response');
        if ($response) {
            $trade = array_get($response, 'trade');
            if (array_get($trade, 'trade_status')) {
                if (array_get($trade, 'trade_status') == 'TRADE_SUCCESS') {
                    return true;
                } elseif (array_get($trade, 'trade_status') == 'TRADE_FINISHED') {
                    return true;
                } else {
                    return false;
                }
            } else {
                return false;
            }
        } else {
            return false;
        }
    }