What is the difference between wrapping a function and replacing it?
PICTURE THIS: RAG CHATBOT
Simple meaning
A wrapper calls the original and adds behavior
WHY — Decorators instead of guessing?
Why interviewers care about Decorators:
contrast on Decorators, not two memorised paragraphs.
the developer, then one case where picking wrong hurts.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1A wrapper calls the
original and adds behavior
- 2replacement returns a completely
different callable and may drop the original.
- 3Wrapping preserves semantics if
you forward arguments and return values.
- 4Tools that introspect __wrapped__
expect the wrapping pattern with functools.wraps.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
A wrapper calls the original and adds behavior replacement returns a completely different callable and may drop the original.