I'm working on the Machine Learning Practitioner Learning Plan, specifically the Data Preparation for Machine Learning course (https://customer-academy.databricks.com/learn/learning-plans/11/machine-learning-practitioner-learni...). The course presents a demo which directs us to work through a lab exercise. However, I can't see anywhere that presents us with a notebook or other materials on which to do the exercise. Where can the lab notebook be obtained?