public function checkDuplicates()
    {
        $shopNumbers = array();
        $files       = scandir(dirname($this->buildConfigFilePath()));

        foreach ($files as $file) {
            if (!is_file($this->buildConfigFilePath($file))) {
                continue;
            }

            $shopgate_config = null;
            /** @noinspection PhpIncludeInspection */
            include($this->buildConfigFilePath($file));
            if (isset($shopgate_config) && isset($shopgate_config['shop_number'])) {
                if (in_array($shopgate_config['shop_number'], $shopNumbers)) {
                    return true;
                } else {
                    $shopNumbers[] = $shopgate_config['shop_number'];
                }
            }
        }

        return false;
    }