code: public static void saveSchema(final LmlParser parser, final Appendable appendable) {
          try {
              new Dtd().getDtdSchema(parser, appendable);
          } catch (final IOException exception) {
              throw new GdxRuntimeException("Unable to append to file.", exception);
          }
      }
docs: Saves DTD schema file containing all possible tags and their attributes. Any problems with the generation will
  be logged. This is a relatively heavy operation and should be done only during development.
  
  @param parser contains parsing data. Used to create mock-up actors. The skin MUST be fully loaded and contain all
  used actors' styles for the generator to work properly.
  @param appendable a reference to the file.
  @see #getDtdSchema(LmlParser, Appendable)
  @see #saveMinifiedSchema(LmlParser, Appendable)