How to use the crontab.crontab.CronRange function in crontab

def get_range(self, *vrange):
        """Return a cron range for this slice"""
        ret = CronRange(self, *vrange)
        if ret.dangling is not None:
            return [ret.dangling, ret]
        return [ret]

def __iter__(self):
        """Return the entire element as an iterable"""
        ret = {}
        # An empty part means '*' which is every(1)
        if not self.parts:
            self.every(1)
        for part in self.parts:
            if isinstance(part, CronRange):
                for bit in part.range():
                    ret[bit] = 1
            else:
                ret[int(part)] = 1
        for val in ret:
            yield val