nl := make([]T, 0, len(a)+len(b))
	i, j := 0, 0
	appendIfUnique := func(t T) []T {
		l := len(nl)
		if l == 0 {
			nl = append(nl, t)
		} else {
			last := nl[l-1]
			if last != t {
				nl = append(nl, t)
			}
		}
		return nl
	}
	for i < len(a) && j < len(b) {
		if a[i] < b[j] {
			nl = appendIfUnique(a[i])
			i++
		} else {
			nl = appendIfUnique(b[j])
			j++
		}
	}
	for ; i < len(a); i++ {