sequence homework 2

from contextlib import suppress


def adv_range(seq):
    for element in seq.split(','):
        with suppress(ValueError):
            if '-' in element:
                start, _, stop = element.partition('-')
                start, stop = int(start), int(stop)
                direction = 1 if start <= stop else -1
                yield from range(start, stop + direction, direction)
            else:
                yield int(element)


def safe_adv_range(seq, constructor=set):
    retval = constructor(adv_range(seq))
    return sorted(retval)