A frozen dataclass in Python
Python interview exercise on Classes & Dataclasses, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write Money as a frozen dataclass with amount (int) and currency (str). Adding two Money values returns a new Money; different currencies raise ValueError. frozen=True makes instances immutable and therefore hashable.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.