Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the scope and closure bugs pattern
Every callback reports the last value, a counter never increments, UnboundLocalError on a variable you can see.
What went wrong: items = [] written in the class body is one list shared by all baskets.
The fix: add def __init__(self): self.items = [] and remove the class-level items.
Remember: create per-object lists and dicts in __init__.
The pattern behind it: scope and closure bugs.
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<iframe src="https://trybughunt.com/embed/f2e9bb9b-9f1b-4314-a5ab-2aab32c2a862" title="Debugging challenge: New basket already has the first basket's item" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/f2e9bb9b-9f1b-4314-a5ab-2aab32c2a862">TryBugHunt</a></p>