The first version of this book was written when Python was at version 3.5 and the asyncio library was still too obtuse to introduce in an introductory text. The library is now much easier to use and I've decided to incorporate it into the materials from the earliest chapters. Music, after all, is event-driven and asyncio is the library that will make it possible for you to interact with the software you write using a hardware MIDI controller and real-time input.
Most of the material will stay the same, but the narrative, examples, and exercises will change. I'm expecting the new material to be available here by June 2021. In the meantime, if you were working through the book in its previous state, you can email me ✉ (this should open your email client) and we'll figure something out.