public function getSpreadsheetFeed($location = null)
    {
        if ($location == null) {
            $uri = self::SPREADSHEETS_FEED_URI;
        } else if ($location instanceof Zend_Gdata_Spreadsheets_DocumentQuery) {
            if ($location->getDocumentType() == null) {
                $location->setDocumentType('spreadsheets');
            }
            $uri = $location->getQueryUrl();
        } else {
            $uri = $location;
        }

        return parent::getFeed($uri, 'Zend_Gdata_Spreadsheets_SpreadsheetFeed');
    }