code: public String toMnemonicString() {
      int value = this.options;
      StringBuilder mnemonicString = new StringBuilder();
      for (Option option : Option.values()) {
        if (value % 2 != 0) {
          mnemonicString.append(option.token);
        }
        value >>= 1;
      }
      return mnemonicString.toString();
    }
docs: Converts this instance of {@link PreserveAttributes} into a String that can be converted to an equivalent
  {@link PreserveAttributes} using {@link PreserveAttributes#fromMnemonicString}. See the latter for more
  information.
  @return a String that can be converted to an equivalent {@link PreserveAttributes} using
  {@link PreserveAttributes#fromMnemonicString}