public function deletePhoto($photoId)
    {
        if (is_null($photoId) || $photoId == '') {
            throw new Exception('The photoId is required to delete a photo.');
        }

        $params = array(
            'method' => 'sp.photo.delete',
            'photo_id' => $photoId
        );

        return $this->_makeApiRequest($params);
    }