code: def available_args(self):
          
          used = list(self.used_args)
          logger.debug('Found used args: %s' % used)
          for arg in list(self.cmd.args.values()):
              if (arg.is_multiple or
                      arg not in used):
                  yield arg
              elif (type(arg.nargs) is int and
                      arg.nargs > 1 and
                      not arg.nargs == used.count(arg)):
                  yield arg
docs: Return args that can be used given
          the current cmd line
  
          rtype: command.Arg generator