return getCrawlerDocumentCharsAsArray(CRAWLER_DOCUMENT_SPACE_CHARS, getCrawlerDocumentSpaceChars());
    }

    default String[] getCrawlerDocumentSpaces() {
        String[] spaces = (String[]) propMap.get(CRAWLER_DOCUMENT_SPACES);
        if (spaces == null) {
            spaces = Arrays.stream(getCrawlerDocumentSpaceCharsAsArray()).mapToObj(Character::toString).toArray(n -> new String[n]);