StringBuilder result = new StringBuilder();

    @Override
    public Appendable append(CharSequence csq) {
      result.append(csq);
      return this;
    }

    @Override
    public Appendable append(char c) {
      result.append(c);
      return this;
    }

    @Override
    public Appendable append(CharSequence csq, int start, int end) {
      result.append(csq, start, end);
      return this;
    }

    StringBuilder result = new StringBuilder();

    @Override
    public Appendable append(CharSequence csq) {
      result.append(csq);
      return this;
    }

    @Override
    public Appendable append(char c) {
      result.append(c);
      return this;
    }

    @Override
    public Appendable append(CharSequence csq, int start, int end) {
      result.append(csq, start, end);
      return this;
    }