static S numberedLines(Map map) {
  ret numberedLines(mapToLines(map));
}

static <A> S numberedLines(Collection<A> l) {
  int i = 0;
  new L<S> lines;
  if (l != null) for (A a : l) lines.add(((++i) + ". " + str(a)));
  ret lines(lines);
}