P46PythonBeginnerDiagnose5 min
Trace a List Mutation That Duplicated Revenue Labels
Trace a small function to find a shared-list mutation that duplicates a revenue label.
#diagnose#lists#mutation
Scenario
A reporting helper receives labels = ['Retail', 'Wholesale'] and appends 'Total' before returning it. A second report unexpectedly starts with an existing Total label.
Problem statement
Identify the failure and explain why downstream totals changed.
Your Task
- Trace the list across two calls.
- Identify the shared-state mutation.
- Give a safe correction.
Related Concepts
ListsMutationFunction contracts
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