Lesson 3: From notebook cells to a project you can trust

Module 1 · Lesson 3 · About 40 minutes · Needs: Module 0 (the assistant's first answer) and Lesson 1 of this module (functions, modules, exceptions)

The situation

The BrightCart assistant from Module 0 lives in notebook cells. It works when you run them in order, with your key pasted into one. Priya wants Dev to run it, then a server, and Sam has one question: where is the key?

A notebook cannot answer that. This lesson turns the cells into a small folder, brightcart/, that another person can install, run and test. One request is traced through: Aisha Rahman (cust-88) asks "How long does standard delivery take?". By the end it runs from a file, the key comes from the environment, a test proves the answer path, and one JSON log line records what happened.