public function has(string $index, array $options = []) : bool
    {
        $separator = isset($options['separator']) ?
            $options['separator'] :
            $this->getOption('separator', '.');
        $value = $this->getData();
        $keys = explode($separator, $index);

        foreach ($keys as $key) {
            if (!is_array($value) || !array_key_exists($key, $value)) {
                return false;
            }

            $value = $value[$key];
        }

        return true;
    }