static Map lambdaMapLike mapKeysAndValues(O f, Map map) {
  ret mapKeysAndValues(f, f, map);
}

static Map mapKeysAndValues(O fKey, O fValue, Map map) {
  if (map == null) null;
  Map m = similarEmptyMap(map);
  for (O key, val : (Map<O>) map)
    m.put(callF(fKey, key), callF(fValue, val));
  ret m;
}

static <A, B> Map<B> mapKeysAndValues(IF1<A, B> f, Map<A> map) {
  ret mapKeysAndValues(f, f, map);
}

static <A, B, C, D> Map<C, D> mapKeysAndValues(IF1<A, C> fKey, IF1<B, D> fValue, Map<A, B> map) {
  if (map == null) null;
  Map<C, D> m = similarEmptyMap(map);
  for (A key, B val : map)
    m.put(fKey.get(key), fValue.get(val));
  ret m;
}

Began life as a copy of #1008376