static <A, B> Map<A, B> filterMapByValuePredicate(Map<A, B> map, IF1<B, Bool> pred) {
  ret filterMap(map, func(A key, B value) -> bool { pred.get(value) });
}

static <A, B> Map<A, B> filterMapByValuePredicate(IF1<B, Bool> pred, Map<A, B> map) {
  ret filterMapByValuePredicate(map, pred);
}