ranges/ranges.go
func (it *inclusiveRangesIt) IsDone() bool {
	if !it.init() {
		return true
	}

	return it.current.IsDone()
}
func (it *inclusiveRangesIt) IsDone() bool {
	if !it.init() {
		return true
	}

	return it.current.IsDone()
}
// IsDone returns false while the iterator is valid
// and can produce another value, via a call to Next()