class PayPalPaymentGateway(PaymentGateway): def process_payment(self, amount): print(f"Processing payment of ${amount} using PayPal.")
stripe_gateway = StripePaymentGateway() paypal_gateway = PayPalPaymentGateway() python 3 deep dive part 4 oop high quality
def start_engine(self): print("The engine is started.") python 3 deep dive part 4 oop high quality