}
  }

  static class UsesEnum {
    private final TimeUnit s;

    public UsesEnum(TimeUnit s) {
      this.s = checkNotNull(s);
    }

    @Override
    public int hashCode() {
      return s.hashCode();
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof UsesEnum) {
        UsesEnum that = (UsesEnum) obj;