Review the Python functions in helpers.py against the behavioral contract in
requirements.txt using static inspection only. Do not execute target code or
inspect tests, solutions, other files, or another reviewer's result. Do not
edit files, use network/APIs, read credentials or install anything. Report all
reproducible behavioral defects with function, valid counterexample,
expected/actual behavior and a short fix. Omit style and out-of-scope
speculation. Do not force any number of findings. State uncertainties.

This is a portable rendering of the shared substantive review instruction.
Original dispatches also named the absolute target paths, lifecycle reporting
commands and reviewer A/B task titles. Those private routing details are omitted.