static <A> L<A> takeLast(L<A> l, int n) {
  return newSubList(l, l(l)-n);
}

static <A> L<A> takeLast(int n, L<A> l) {
  ret takeLast(l, n);
}

static S takeLast(int n, S s) {
  ret substring(s, l(s)-n);
}

static S takeLast(S s, int n) {
  ret substring(s, l(s)-n);
}