return null;
        } catch (final ChildUrlsException e) {
            throw new DataStoreCrawlingException(url,
                    "Redirected to " + e.getChildUrlList().stream().map(RequestData::getUrl).collect(Collectors.joining(", ")), e);
        } catch (final Exception e) {
            throw new DataStoreCrawlingException(url, "Failed to add: " + dataMap, e);
        }
    }