code: public void serialize(final OutputStream out) throws IOException {
      final Writer writer = new BufferedWriter(new OutputStreamWriter(out));
      for (final Map.Entry<String, String> entry : this.multiMap.entries()) {
        writer.write(
            entry.getKey() + IOUtils.TAB_DELIMITER + entry.getValue() + "\n");
      }
      writer.flush();
    }
docs: Serialize the lexicon in the original format.
  
  @param out
  the output stream
  @throws IOException
  if io problems