static <A> Pair<L<A>> filterAntiFilter(Iterable<A> c, O pred) {
  new L<A> yes;
  new L<A> no;
  if (c != null) for (A o : c)
    (isTrue(callF(pred, o)) ? yes : no).add(o);
  ret pair(yes, no);
}

static <A> Pair<L<A>> filterAntiFilter(Iterable<A> c, IF1<A, Bool> pred) {
  ret filterAntiFilter(c, (O) pred);
}

static <A> Pair<L<A>> filterAntiFilter(IF1<A, Bool> pred, Iterable<A> c) {
  ret filterAntiFilter(c, pred);
}

static <A> Pair<L<A>> filterAntiFilter(O pred, Iterable<A> c) {
  ret filterAntiFilter(c, pred);
}

Began life as a copy of #1017203