handle: A Range that handles an Exception

When a Exception occurs inside a range chaining the whole chain dies usually. The Handle range fixes that, as it catches a defined exception and calls an user defined handler on it.
It looks like this `unittest` block is identical to the previous one save for whitespace differences and the fact that there is no cast in the second `map` lambda in this one (and the lack of cast would appear to make the `foreach` pointless here). So, unless I'm missing something, this `unittest` block should probably just be removed.