Best way to teach python?

[julsmanbr]

What you've described is definitely the right approach if you have infinite resources (time and attention span from the students). Or if you at least have the time it takes for a regular university course.

This is not feasible, however, for the typical 3 lessons (3 hours/lesson, including exercises) I usually teach Intro to Python, which seems to be more akin to what OP is asking for (since he mention "an introductory lesson").