Build Python Apps Like LEGO — Composition Guide (Day 12)

"Favour composition over inheritance" — every senior engineer says it, but what does it actually mean in Python? In this Day 12 video, you'll finally understand the difference, know when to use each, and build a full Flipkart-style order system using composition from scratch. In this video, you'll learn: ✅ What composition is & how it differs from inheritance ✅ The IS-A vs HAS-A test — the simplest way to decide ✅ Why deep inheritance chains cause maintenance nightmares ✅ How to swap components at runtime without breaking anything ✅ Full Python code: E-commerce Order System (Flipkart/Amazon style) — Customer, Address, PaymentInfo, OrderItem & Order classes ✅ GST calculation, invoice printing & status tracking — all composed! ✅ Case Study — How Stripe's payment system is built with composition ✅ Practice Problem: Apollo/Fortis Hospital Patient Management System 🔥 After this, you'll write cleaner, more flexible Python — the way it's done in production at top tech companies. ━━━━━━━━━━━━━━━━━━━━━ 💬 CONNECT & RESOURCES ━━━━━━━━━━━━━━━━━━━━━ 👍 If IS-A vs HAS-A finally clicked, LIKE the video — it helps this series reach more Python learners in India! 🔔 SUBSCRIBE to PriyabhAIVlog for daily Python & AI/ML tutorials built for working professionals. 💬 Comment below: Have you ever been burned by a deep inheritance chain at work? Tell me the story! 👇 #PythonOOP #CompositionOverInheritance #PythonDesignPatterns #LearnPython #PriyabhAIVlog