How to use the biblib.services.metajson_service.pretty_print_document function in biblib

document["resources"] = [resource]

    # subjects[]
    if endnote_import_keywords and keywords:
        for keyword in keywords.split():
            document.set_key_with_value_type_in_list("subjects", keyword, "topic")

    # title, title_alternative, title_abbreviated, title_translated
    document["title"] = title
    if title_alternative:
        document["title_alternatives"] = [{"title": title_alternative}]
    if title_abbreviated:
        document["title_abbreviateds"] = [{"title": title_abbreviated}]

    #logging.debug("# endnote_type: {}".format(endnote_type))
    metajson_service.pretty_print_document(document)
    return document

if series:
        document["part_number"] = series

    # isbn -> identifiers[].id_value = isbn
    isbn = get_field(entry, 'isbn')

    # file -> todo
    myfile = get_field(entry, 'file')

    # keywords -> todo
    keywords_field = get_field(entry, 'keywords')
    if keywords_field:
        keywords = re.split(r',', get_field(entry, 'keywords').lower())

    logging.info("# BibTeX type: {}".format(bibtex_type))
    metajson_service.pretty_print_document(document)
    return document

def mods_xmletree_to_metajson(mods, source, rec_id_prefix):
    """ MODS xmletree -> MetaJSON Document """
    if mods is None:
        return None

    # @version -> null
    #mods_version = mods.get("version")
    #logging.debug("# mods_version: {}".format(mods_version))

    document = mods_root_or_related_item_to_metajson(mods, None)

    # source
    if source:
        document["rec_source"] = source

    metajson_service.pretty_print_document(document)
    return document

resource["rec_modified_date"] = field_995.get_subfields('s')[0]
            # $u -> notes[i]/value ex: Ceci est une note
            if field_995.get_subfields('u'):
                resource["notes"] = [{"value":field_995.get_subfields('u')[0],"language":"und"}]
            # $v -> issue_number ex: Vol. 52, no 1>6, 2002 : vol. relié
            if field_995.get_subfields('v'):
                resource["issue_number"] = field_995.get_subfields('v')[0]
            # $w -> issue_date ex: 2002
            if field_995.get_subfields('w'):
                resource["issue_date"] = field_995.get_subfields('w')[0]
            if resource:
                resources.append(resource)
    if resources is not None:
        document["resources"] = resources

    metajson_service.pretty_print_document(document)
    return document

# language
    doc_language = None
    if tei_languages:
        languages = []
        for tei_language in tei_languages:
            language = tei_language.get("ident")
            languages.append(language)
        if languages:
            document["languages"] = languages
            doc_language = languages[0]

    # title
    document.update(get_tei_titles_to_metason(tei_titlestmt, doc_language))

    metajson_service.pretty_print_document(document)
    metajson_service.print_document(document)
    return document

keywords = {main_language: []}
    if subject_keywords:
        keywords[main_language].extend(subject_keywords)
    if subject_topics:
        keywords[main_language].extend(subject_topics)
    if subject_agents:
        subject = Subject()
        subject["agents"] = subject_agents
        subjects.append(subject)
    if subjects:
        document["subjects"] = subjects
    if keywords[main_language]:
        document["keywords"] = keywords

    logging.info("# Summon ContentType: {}".format(sum_type))
    metajson_service.pretty_print_document(document)
    return document

rec_type = ris_document_type_to_metajson_document_type[ris_type]
                document["rec_type"] = rec_type
                if ris_type in ris_document_type_to_metajson_document_is_part_of_type:
                    is_part_of_rec_type = ris_document_type_to_metajson_document_is_part_of_type[ris_type]
                    is_part_of = Document()
                    is_part_of["rec_type"] = is_part_of_rec_type
                    document["is_part_ofs"] = [is_part_of]
            elif key == RIS_KEY_END:
                # record end -> return the result
                # verify the is_part_ofs[0]["title"]
                if "is_part_ofs" in document and "title" not in document["is_part_ofs"][0] and "title_abbreviateds" in document["is_part_ofs"][0]:
                    document["is_part_ofs"][0]["title"] = document["is_part_ofs"][0]["title_abbreviateds"][0]["title"]
                    del document["is_part_ofs"][0]["title_abbreviateds"]

                logging.info("# RIS type: {}".format(ris_type))
                metajson_service.pretty_print_document(document)
                yield document
            else:
                # process key value
                #logging.debug("key: {}; value: {}".format(key, value))
                if key == "ID":
                    document["rec_id"] = value
                elif key in ["T1", "TI", "CT"] or (key == "BT" and ris_type in [RIS_TYPE_BOOK, RIS_TYPE_UNPB]):
                    # Title Primary -> title
                    document["title"] = value
                elif key in ["JF", "JO"] or (key == "BT" and ris_type not in [RIS_TYPE_BOOK, RIS_TYPE_UNPB]):
                    # Title Secondary -> is_part_of["title"]
                    document.add_is_part_of_title(value)
                elif key in ["JA", "J1", "J2", "T2"]:
                    # Title Secondary -> is_part_of["title_abbreviateds"][O]["title"]
                    document.add_is_part_of_title_abbreviated(value)
                elif key == "T3":