public static function concatPath($folderPath, $filePath = null)
    {
        if (is_array($folderPath)) {
            $fullPath = '';
            foreach ($folderPath as $path) {
                $fullPath = static::concatPath($fullPath, $path);
            }
            return static::fixPath($fullPath);
        }

        if (empty($filePath)) {
            return static::fixPath($folderPath);
        }
        if (empty($folderPath)) {
            return static::fixPath($filePath);
        }

        if (substr($folderPath, -1) == static::getSeparator() || substr($folderPath, -1) == '/') {
            return static::fixPath($folderPath . $filePath);
        }
        return $folderPath . static::getSeparator() . $filePath;
    }