static <A> A firstThat(Collection<A> l, O pred) {
  for (A a : unnull(l))
    if (checkCondition(pred, a))
      ret a;
  null;
}

static <A> A firstThat(Collection<A> l, IF1<A, Bool> pred) {
  ret firstThat(l, (O) pred);
}

static <A> A firstThat(IF1<A, Bool> pred, Collection<A> l) {
  ret firstThat(l, pred);
}