An oldie but goodie. Beazley did a follow-up to this at PyCon 2014, a 3-hour tutorial on generators. Very much worth a watch! It's called "Generators: The Final Frontier".
Pycon tutorials are held before the main conference at an extra charge for topics that are better suited to be taught over a longer period of time than will fit in a regular 30-45 minute talk session.
https://www.youtube.com/watch?v=5-qadlG7tWo