static bool allContainAllCharsIC(Collection<S> l, S chars) {
  L<Char> charList = chars(upper(chars));
  for (S s : unnull(l)) {
    HashSet<Char> set = asHashSet(charList);
    removeAll(set, chars(upper(s)));
    if (nempty(set)) false;
  }
  true;
}