static <A, B super S> S mapGetString(Map<A, B> map, A a) {
  ret map == null || a == null ? null : (S) map.get(a);
}

static <A, B super S> S mapMethodLike mapGetString(A a, Map<A, B> map) {
  ret map == null || a == null ? null : (S) map.get(a);
}