Week 2 exercise 4.3

Great! The important thing to realize is that @kenb’s point there is a completely general one: every time you close and reopen the notebook or restart the “Kernel”, you need to rerun all the previous cells in the notebook to populate the “namespace” that Ken described. It looks misleading when you open the notebook, because you see all the printed output from the last time you run things. But the point is that the “runtime state” in memory (the “namespace”) is not populated and needs to be recreated every time. There is a topic about this on the FAQ Thread, which is worth a look just on general principles. :nerd_face: