Hello @norvig and @MrDupin, currently the Decision Tree Learner part in learning.ipynb does not contain any examples of how the algorithm works. There aren't any applications of the Decision Tree Learner in learning_apps.ipynb either. I was thinking that maybe to better describe the Decision Tree part, we could add a sample example of how it will perform with iris dataset and what it may learn.
I was also thinking that maybe we could add some tree graph visualisations, generated using networkx, to show how the tree is actually created and what it learns in each step. Something like these tree-graphs at the end of the notebook (I still have to do some clean-up).