Some of the examples in the book violate the Zen of Python. So I wouldn't even call them pythonic or idiomatic in the first place.

E.g.:

`contains_zero` violates "There should be one-- and preferably only one --obvious way to do it."

`should_raise_shields` violate "Explicit is better than implicit."

`linsolve` and `contains_duplicate` violate "Readability counts."