code: private String getEffectiveValue(Map<String, Option> options, CliOption opt) {
          final String shortOpt = opt.value();
          if (opt.hasArg()) {
              if (options.containsKey(shortOpt)) {
                  return options.get(shortOpt).getValue();
              }
              return opt.defaultValue();
          }
          return Boolean.toString(options.containsKey(opt.value()));
      }
docs: Returns the effective value for the specified option.
  
  @param options
  the parsed option
  @param opt
  the cli option annotation for which the actual argument should be retrieved
  
  @return the effective value for the given option <ul> <li>If the option should have an argument, and an argument
  is provided, the provided argument is returned</li> <li>If the option should have an argument, and none is
  specified, the default value is returned</li> <li>If the option has no argument, and is specified, "true" is
  returned</li> <li>If the option has no argument, and is not specifeid, "false" is returned</li> </ul>