Lab: Model v2, found and tested honestly
Module 6 · Lab · About 60 minutes · Needs: lessons 1 and 2 of this module, and the Module 5 lab (or nothing: Step 1 rebuilds Modules 1 to 5)
What you are building
Adaeze's question for this module is the fifth of the course's five: "Can you reproduce last month's model exactly?" Before Kestrel can answer it, every run has to leave a record, and before anyone calls a new model better, the claim has to survive a fair comparison. The lessons built both halves. This lab uses them on the real thing: model v1 from the Module 3 lab (kestrel/train_v1.py, a tuned LightGBM with Platt scaling), and a challenger, model v2, found by a tracked search.
The lab adds kestrel/train_v2.py (the recipe, the search, the model and three helpers) and reports/experiments.md, generated from the MLflow store. It makes the repository a Git repository, so every run records the commit it came from, writes three entries in the experiment log, one of them negative, and spends the locked test weeks on their one look. No cell calls a hosted model.
Open a new Colab notebook, call it module-06-lab.ipynb, and run each cell in order.