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Python · Mid-level · Theory

You overrode __eq__ on a Money class, and when you tried to put an object in a set, you got TypeError: unhashable type. Why did this happen, and how do you correctly implement equality and hashing?

~4 min by voice

How to approach it

This checks your understanding of the hashing protocol in Python: why __eq__ without __hash__ makes an object unhashable, what contract connects equality and the hash, and why set and dict keys must be immutable.

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The interviewer will ask this question and listen. Think out loud and ask for a hint if you need one. When you're done, pause or tap “That's my answer”. In about a minute, your score and the points you covered show up here.

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Best with headphones · ~4 min