Python OOP Payment Processing | Abstract Classes, Inheritance & Runtime Polymorphism

Python OOP Payment Processing System | Abstract Classes and Runtime Polymorphism In this video, we build a simple Payment Processing System using Python Object-Oriented Programming. This project demonstrates how an abstract parent class can define a common payment interface while different payment methods provide their own implementation. We will create an abstract Payment class and implement three payment methods: CreditCardPayment UPIPayment NetBankingPayment The main goal is to understand abstraction, inheritance, method overriding, and runtime polymorphism through a practical payment-processing example. ABSTRACT PAYMENT CLASS The Payment class will contain an abstract pay() method. The abstract method defines what every payment type must implement without providing a specific payment implementation in the parent class. PAYMENT TYPES CreditCardPayment Implements payment processing using credit card details. UPIPayment Implements payment processing using UPI details. NetBankingPayment Implements payment processing using banking details. KEY OOP CONCEPTS COVERED Abstract classes Abstract methods ABC @abstractmethod Inheritance Method overriding Runtime polymorphism Classes and objects Constructors Instance methods Multiple objects Real-world OOP design RUNTIME POLYMORPHISM The most important concept in this project is runtime polymorphism. We can create different payment objects and call the same method: pay() For example: CreditCardPayment → pay() UPIPayment → pay() NetBankingPayment → pay() The method name remains the same, but the behavior changes depending on the object being used. This demonstrates the idea: Same interface → Different implementation REAL-WORLD PAYMENT EXAMPLE An online application may support multiple payment methods. A customer might choose: Credit Card UPI Net Banking The application should not need completely different calling logic for every payment type. Instead, each payment class implements the common pay() method and the application can call that method on different payment objects. APPLICATION FLOW Create Payment Objects ↓ Credit Card Payment ↓ UPI Payment ↓ Net Banking Payment ↓ Call pay() on Each Object ↓ Observe Different Implementations This demonstrates how polymorphism makes code more flexible and easier to extend. WHY USE AN ABSTRACT CLASS? The Payment class represents a common concept rather than one specific payment implementation. By making pay() an abstract method, every child payment class is required to provide its own implementation. This creates a common contract for all payment types. For example: Payment ↓ CreditCardPayment UPIPayment NetBankingPayment If another payment method needs to be added later, such as WalletPayment, it can inherit from Payment and implement pay(). WHAT YOU SHOULD UNDERSTAND AFTER THIS VIDEO By the end of this project, you should understand: What is an abstract class? What is an abstract method? Why do we use @abstractmethod? What is inheritance? What is method overriding? What is runtime polymorphism? How does the same method behave differently for different objects? Why is abstraction useful in real-world applications? How can new payment methods be added easily? GITHUB REPOSITORY https://github.com/Ram14312/polymorph... PREVIOUS PYTHON OOP PROJECTS Python Banking Application: YOUR_PREVIOUS_VIDEO_LINK Python Employee and Developer Inheritance: YOUR_PREVIOUS_VIDEO_LINK Python Online Learning Platform: YOUR_PREVIOUS_VIDEO_LINK Python Student Management System: YOUR_PREVIOUS_VIDEO_LINK Python Vehicle Rental Application: YOUR_PREVIOUS_VIDEO_LINK Python Super30 Learning Platform: YOUR_PREVIOUS_VIDEO_LINK Python E-Commerce Product Management: YOUR_PREVIOUS_VIDEO_LINK Python Employee Management System: YOUR_PREVIOUS_VIDEO_LINK WHO SHOULD WATCH? This project is useful for: Python beginners Students learning OOP Developers strengthening Python fundamentals Coding interview preparation Backend developers Automation developers AI and ML engineers GenAI engineers If you found this video useful: 👍 Like the video 💬 Comment your doubts 📢 Share with someone learning Python 🔔 Subscribe for more Python and AI Engineering content Learn • Build • Practice • Grow 🚀 #Python #PythonOOP #AbstractClass #RuntimePolymorphism #PythonInheritance #MethodOverriding #ObjectOrientedProgramming #PythonProject #LearnPython #PythonProgramming #CodingPractice #AIEngineering