12 August 2026 · 6 min read
Python's traceback tells you where execution stopped, but the final line is only the symptom. Read upward for the failing call and then inspect the values that reached it.
Copy the traceback, reproduce with the smallest input, print or inspect the relevant types and values, make one change, then add a test for the failure. Avoid hiding errors with broad except blocks.
Assignment Byte can review Python scripts, notebooks, APIs and tests with a walkthrough of the diagnosis.