Sonata\Component\Payment\Paypal::isBasketValid PHP Method

    public function isBasketValid(BasketInterface $basket)
    {
        if ($basket->countBasketElements() == 0) {
            return false;
        }
        foreach ($basket->getBasketElements() as $element) {
            $product = $element->getProduct();
            if ($product->isRecurrentPayment() === true) {
                return false;
            }
        }
        return true;
    }