code: public static String parse(String commandLine, final CommandLineParser.CallbackHandler handler, boolean strict) throws CommandFormatException {
          if(commandLine == null) {
              return null;
          }
          final ParsingStateCallbackHandler callbackHandler = getCallbackHandler(handler);
          return StateParser.parse(commandLine, callbackHandler, InitialState.INSTANCE, strict);
      }
docs: Returns the string which was actually parsed with all the substitutions performed