Module 03 — Python Memory, Object Model & Type System

To write mid-to-senior level Python, you must stop treating variables as "boxes that hold values" and understand CPython object references, mutability, lazy generators, structural typing (Protocol), and deterministic resource management (with).

Lessons in this Module

1. 01 — Object References, Mutability, Recycling & Memory Leaks Understand id(), reference counting, cyclic garbage collection, shallow vs. deep copies, and the classic mutable default argument trap.
2. 02 — The Python Data Model, Iterators & $O(1)$-Memory Generators Implement __iter__, __next__, and generator pipelines (yield) that process 50 GB log files using less than 5 MB of RAM.
3. 03 — Strict Typing, Generics, Protocol & Runtime Boundaries Design explicit interfaces with Protocol (duck typing verified statically), generics, immutable @dataclass(frozen=True, slots=True), and boundary validation.
4. 04 — Context Managers (with), RAII & Exception Hierarchies Guarantee database connections, locks, and sockets never leak under exceptions using __enter__/__exit__, @contextmanager, and domain exception chaining.