protected function getKeyPath($key)
    {
        if (empty($this->options['parents'])) {
            return $key;
        }

        if (is_string($this->options['parents'])) {
            $this->options['parents'] = explode('.', $this->options['parents']);
        }

        if (is_string($key)) {
            $key = explode('.', $key);
        }

        return array_merge((array) $this->options['parents'], (array) $key);
    }