static <A, B> L<A> reverseLookupAll(B value, Map<A, B> map) {
  ret reverseLookupAll(map, value);
}

static <A, B> L<A> reverseLookupAll(Map<A, B> map, B value) {
  new L<A> l;
  if (map != null && value != null) for (A key : map.keySet())
    if (eq(map.get(key), value))
      l.add(key);
  ret l;
}