protected function libNth($args)
{
$list = $this->coerceList($args[0]);
$n = $this->assertNumber($args[1]);
if ($n > 0) {
$n--;
} elseif ($n < 0) {
$n += count($list[2]);
}
return isset($list[2][$n]) ? $list[2][$n] : static::$defaultValue;
}