query.go
func Any(iterator Enumerable) bool {
	done := make(chan struct{})
	defer close(done)

	for range iterator.Enumerate(done) {
		return true
	}
	return false
}
func Any(iterator Enumerable) bool {
	done := make(chan struct{})
	defer close(done)

	for range iterator.Enumerate(done) {
		return true
	}
	return false
}
// Any tests an Enumerable to see if there are any elements present.