code: private static void usage(ArgOptions options) {
          System.out.println(
              "Fanmod 1.0, " +
              "usage: java -jar fanmod.jar [options] input.graph output.serialized \n\n" 
              + options.prettyPrint() +
              "\nThe edge file format is:\n" +
              "   vertex1 vertex2 [edge_label]\n" +
              OptionDescriptions.HELP_DESCRIPTION);
      }
docs: Prints the options and supported commands used by this program.
  
  @param options the options supported by the system