static <A> A firstInstanceOf(Iterable i, Class<A> c) {
  if (i == null) null;
  c = primitiveToBoxedTypeOpt(c);
  for (O o : i)
    if (isInstance(c, o))
      ret (A) o;
  null;
}

static <A> A firstInstanceOf(Class<A> c, Iterable i) {
  ret firstInstanceOf(i, c);
}