protected static function parseAtom(\SimpleXMLElement $xml)
    {
        if (!isset($xml->entry)) {
            return false;
        }

        $url = '';

        foreach ($xml->link as $link) {
            $attributes = $link->attributes();

            if (empty($attributes->href) || ((string) $attributes->rel === 'self')) {
                continue;
            }
            $url = (string) $attributes->href;
            break;
        }

        return [
            'url' => $url,
            'items' => self::getAtomEntries($xml->entry),
        ];
    }