public function paymentButton(Environment $environment, $text = null, $amount = null, $currency = null, $style = 'btn btn-lg btn-primary')
    {
        return $environment->render('@c975LPayment/fragments/paymentButton.html.twig', array(
                'text' => $text,
                'amount' => $amount,
                'currency' => strtolower($currency),
                'style' => $style,
            ));
    }