public static function textBatchUpdate(Api\MtBatchTextSmsUpdate $batch)
    {
        $fields = Serialize::_batchUpdateHelper($batch);

        $fields['type'] = 'mt_text';

        if (null != $batch->getBody()) {
            $fields['body'] = $batch->getBody();
        }

        if (null != $batch->getParameters()) {
            if ($batch->getParameters() === Api\Reset::reset()) {
                $fields['parameters'] = null;
            } else {
                $fields['parameters'] = $batch->getParameters();
            }
        }

        return Serialize::_toJson($fields);
    }