Sylius\Component\Payment\Resolver\DefaultPaymentMethodResolverInterface::getDefaultPaymentMethod PHP Method

    public function getDefaultPaymentMethod(PaymentInterface $payment);

 /**
  * @param PaymentInterface $payment
  * @param OrderInterface $order
  *
  * @return null|PaymentMethodInterface
  */
 private function getDefaultPaymentMethod(PaymentInterface $payment, OrderInterface $order)
 {
     try {
         $payment->setOrder($order);
         $paymentMethod = $this->defaultPaymentMethodResolver->getDefaultPaymentMethod($payment);
         return $paymentMethod;
     } catch (UnresolvedDefaultPaymentMethodException $exception) {
         return null;
     }
 }