Why do you consider that naive?

Also, I wouldn't use epsilon, because that is a very small number and is related to representation of numbers. I would instead use a larger "tolerance" value, in `if |a-b| < tol ...` because that indicates the expected accuracy of your algorithm (unless you're really working with 1e-80 tolerance?). But TFA explains that.

But back to point (a) is that not reasonable? (If not, I've got some code to change... :)