What you see here is an early version of the book. We have yet to get everything working right and rewritten for Python. Or even to get the book testing systems in place.
If you’re here because you’re curious, that’s great. But please don’t expect too much from the book just yet. When we get it to a point where everything compiles and all the Java references, etc. have been rewritten out, then this note will disappear. Until then, caveat emptor.