}
  }

  static class HasAnInterface implements Serializable {
    private final AnInterface i;

    public HasAnInterface(AnInterface i) {
      this.i = i;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof HasAnInterface) {
        HasAnInterface that = (HasAnInterface) obj;
        return i.equals(that.i);
      } else {