Module 6 diagnostic evidence

Complete this before opening the separate answer.

1. Contract in my own words:
2. Initial input / expected output / actual output:
3. A smaller input that still fails, with its expected/actual result:
4. Trace: executed line and value of count after that line:
5. Hypothesis: the operation that could explain the mismatch:
6. One proposed change and my predicted effect:
7. Result after the change:
8. Regression tests retained, including empty input:
9. Separate traceback experiment: failing operation, observed input and upstream source for "20minutes":

A correct final number without this evidence does not demonstrate the debugging process.