[Python-ideas] Yet another sum function (fractions.sum)

[random832 at fastmail.us]

On Wed, Aug 21, 2013, at 11:22, Eric V. Smith wrote:
> Exactly. Here's an extreme case: Say I do an operation, unexpectedly get
> a negative number,

Why can that operation return a negative number instead of raising an
exception in the situation where it would return a negative number? I
mean, if you want to get your exceptions as early as possible, however
unpythonic that may be, that's the next logical step. Why do we need an
implicit* wall between real and complex numbers, but not between
positive and negative numbers, or integers and floats?

*as in "explicit is better than", as in check your results yourself.