public function find($search = null)
    {
        $results = array();
        if (empty($search)) {
            $results = $this->config;
        } elseif (is_scalar($search)) {
            $results = array_filter($this->config, function ($value, $key) use ($search) {
                    return strpos($key, $search) !== false;
                });
        } elseif (is_array($search)) {
            foreach ($search as $key) {
                if (!is_array($results)) $results = array();
                $results[$key] = $this->get($key);
            }
        }
        return $results;
    }