static <A> L<A> printNumberedLines(Collection<A> l) {
  int i = 0;
  for (A a : l) print((++i) + ". " + str(a));
  ret l;
}

static void printNumberedLines(O[] l) {
  printNumberedLines(asList(l));
}

static void printNumberedLines(O o) {
  printNumberedLines(lines(str(o)));
}