Question 1

What is composition versus inheritance?

Accepted Answer

**Target Audience:** Developers who can write classes and subclasses and want to know how to choose between the two main ways of reusing code.
**Difficulty:** Medium
**Python version:** Behaviour checked on CPython 3.11.17, 3.12 and 3.13, and in the page runner (Pyodide 0.25.1, CPython 3.11.3).

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact words an interviewer expects. All output shown was produced

Question 2

What are decorators in Python?

Accepted Answer

**Target Audience:** Python beginners who have written functions, up to candidates preparing for mid-level interviews
**Difficulty:** Medium
**Python version:** behaviour checked on CPython 3.11 (python3.11 and the in-page Pyodide 0.25.1 runtime)

> **How to read this doc:** Every idea is first explained in plain words. When a term has a precise name an interviewer expects to hear, it is introduced as a 📌 **Interview term** callout. The Quick Glossary at the end lists all of them.

## 1. Why Th

Question 3

What is a decorator factory (a decorator with arguments)?

Accepted Answer

**Target Audience:** Developers who can write a plain decorator and want configurable ones
**Difficulty:** Medium
**Python version:** behaviour checked on CPython 3.11 (python3.11 and the in-page Pyodide 0.25.1 runtime)

> **How to read this doc:** Every idea is first explained in plain words. When a term has a precise name an interviewer expects to hear, it is introduced as a 📌 **Interview term** callout. The Quick Glossary at the end lists all of them.

## 1. Why This Even Matters — A Story F

Question 4

Why use functools.wraps when writing decorators?

Accepted Answer

**Target Audience:** Developers who can write a basic decorator and want to know why the extra line matters
**Difficulty:** Medium
**Python version:** behaviour checked on CPython 3.11 (python3.11 and the in-page Pyodide 0.25.1 runtime); the 3.12 and 3.13 attribute list was printed on those interpreters

> **How to read this doc:** Every idea is first explained in plain words. When a term has a precise name an interviewer expects to hear, it is introduced as a 📌 **Interview term** callout. The

Question 5

What does the functools module offer?

Accepted Answer

**Target Audience:** Python developers who write decorators, sort objects or cache expensive calls; candidates asked the open-ended "what is in functools?".
**Difficulty:** Medium
**Python version:** Behaviour checked on CPython 3.11.17 and in the page runner (Pyodide 0.25.1, CPython 3.11.3).

> **How to read this doc:** Each idea is explained in plain words first, then tagged with `📌 Interview term:` — that is the exact vocabulary an interviewer expects to hear. Every output shown was printed

PYTHONDECODED.

Medium

What is composition versus inheritance?

What are decorators in Python?

What is a decorator factory (a decorator with arguments)?

Why use functools.wraps when writing decorators?

What does the functools module offer?