Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the mutation and copying bugs pattern
Assignment does not copy, a shallow copy still shares its contents, and mutating methods return None.
What went wrong: round() changes the number, not how it looks. 2.5 is still 2.5, and str() never adds zeros.
The fix: return f"${amount:.2f}"
Remember: use round() for maths and :.2f for display.
The pattern behind it: mutation and copying bugs.
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<iframe src="https://trybughunt.com/embed/906d22e3-e695-4abf-b561-88eb341ab9b5" title="Debugging challenge: Prices show $2.5 instead of $2.50" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
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