code: private void writeDomains() throws IOException {
      int domIndex = 0;
      for (String[] domain : model.scoringDomains()) {
        if (domain == null) continue;
        startWritingTextFile(String.format("domains/d%03d.txt", domIndex++));
        for (String category : domain) {
          writeln(category.replaceAll("\n", "\\n"));  // replace newlines with "\n" escape sequences
        }
        finishWritingTextFile();
      }
    }
docs: Create files containing domain definitions for each categorical column.