I saw the examples differently; first the author notes that it is easy to mask a private attribute and that docs would not help, I believe this was its main poi

I saw the examples differently; first the author notes that it is easy to mask a private attribute and that docs would not help, I believe this was its main point. secondly and less importantly he notes that (with some weird naming practice though) _Foo__bar might again look like something you could define. here i'm stretching my python knowledge so i could be wrong (for example i don't know if hinheritance affects the extended name...) Anyhow i think the first one was the main point: "accidental and hard to debug modification of private field"