code: private static void exportSymbols(SymbolTable syms, String filename) {
      if (syms == null) {
        return;
      }
  
      try (PrintWriter out = new PrintWriter(new FileWriter(filename))) {
        for (ObjectIntCursor<String> sym : syms) {
          out.println(sym.key + "\t" + sym.value);
        }
      } catch (IOException e) {
        throw Throwables.propagate(e);
      }
    }
docs: Exports a symbols' map to the openfst text format
  
  @param syms     the symbols' map
  @param filename the the openfst's symbols filename