How to use the biblib.util.xmletree.get_element_text function in biblib

def get_rml_element_text(rml, element):
    element_xmletree = rml.find(xmletree.prefixtag("rml", element))
    return xmletree.get_element_text(element_xmletree)

def get_rml_turnovers(rml):
    """ turnover -> turnovers """
    result = {}
    rml_turnovers = rml.findall(xmletree.prefixtag("rml", "turnover"))
    if rml_turnovers is not None:
        turnovers = []
        for rml_turnover in rml_turnovers:
            if rml_turnover is not None:
                turnover = {}

                turnover.update(xmletree.get_element_attribute_and_set_key(rml_turnover, "currency", "currency"))
                turnover.update(xmletree.get_element_attribute_and_set_key(rml_turnover, "year", "year"))
                turnover["value"] = xmletree.get_element_text(rml_turnover)

                if turnover:
                    turnovers.append(turnover)
        if turnovers:
            result["turnovers"] = turnovers
    return result

conditions.append(value)
                    if conditions:
                        sap["conditions"] = conditions

            # copyright -> copyright
            sap.update(get_rml_element_text_and_set_key(rml_romeo, "copyright", "copyright"))

            # copyrightlinks -> copyright_urls
            rml_copyrightlinks = rml_romeo.find(xmletree.prefixtag("rml", "copyrightlinks"))
            if rml_copyrightlinks is not None:
                rml_copyrightlinks_list = rml_copyrightlinks.findall(xmletree.prefixtag("rml", "copyrightlink"))
                if rml_copyrightlinks_list is not None:
                    copyright_urls = []
                    for rml_copyrightlink in rml_copyrightlinks_list:
                        copyrightlinktext = xmletree.get_element_text(rml_copyrightlink.find(xmletree.prefixtag("rml", "copyrightlinktext")))
                        copyrightlinkurl = xmletree.get_element_text(rml_copyrightlink.find(xmletree.prefixtag("rml", "copyrightlinkurl")))
                        copyright_url = metajson_service.create_url(copyrightlinkurl, None, None, copyrightlinktext, None, None)
                        copyright_urls.append(copyright_url)
                    if copyright_urls:
                        sap["copyright_urls"] = copyright_urls

            # paidaccess -> paid_access
            rml_paidaccess = rml_romeo.find(xmletree.prefixtag("rml", "paidaccess"))
            if rml_paidaccess is not None:
                paid_access = {}

                # paidaccessname -> label
                paid_access.update(get_rml_element_text_and_set_key(rml_paidaccess, "paidaccessname", "label"))

                # paidaccessurl -> url
                paid_access.update(get_rml_element_text_and_set_key(rml_paidaccess, "paidaccessurl", "url"))

def get_rml_money_and_set_key(rml, element, key):
    """ element -> key """
    result = {}
    rml_element = rml.find(xmletree.prefixtag("rml", element))
    if rml_element is not None:
        money = {}

        # currency -> currency
        money.update(xmletree.get_element_attribute_and_set_key(rml_element, "currency", "currency"))

        # text -> value
        money["value"] = xmletree.get_element_text(rml_element)

        if money:
            result[key] = money
    return result

def get_mods_element_text(rml, element, strip=True):
    element_xmletree = rml.find(xmletree.prefixtag("mods", element))
    return xmletree.get_element_text(element_xmletree, strip)

def get_mods_elements_text(rml, element):
    elements_xmletree = rml.findall(xmletree.prefixtag("mods", element))
    if elements_xmletree is not None:
        results = []
        for element_xmletree in elements_xmletree:
            if element_xmletree is not None:
                results.append(xmletree.get_element_text(element_xmletree))
        if results:
            return results
    return None

result = {}
    rml_ims = rml.findall(xmletree.prefixtag("rml", "instantMessage"))
    if rml_ims is not None:
        ims = []
        for rml_im in rml_ims:
            if rml_im is not None:
                # @preferred -> preferred
                preferred = xmletree.get_element_attribute_as_boolean(rml_im, "preferred")
                # @relationType -> relation_type
                relation_type = rml_im.get("relationType")
                # @service -> service
                service = rml_im.get("service")
                # @visible -> visible
                visible = xmletree.get_element_attribute_as_boolean(rml_im, "visible")
                # value
                value = xmletree.get_element_text(rml_im)

                im = metajson_service.create_instant_message(value, service, preferred, relation_type, visible)
                if im:
                    ims.append(im)
        if ims:
            result["instant_messages"] = ims
    return result

def get_rml_uris(rml):
    """ uri -> urls """
    result = {}
    rml_uris = rml.findall(xmletree.prefixtag("rml", "uri"))
    if rml_uris is not None:
        urls = []
        for rml_uri in rml_uris:
            if rml_uri is not None:
                preferred = xmletree.get_element_attribute_as_boolean(rml_uri, "preferred")
                relation_type = rml_uri.get("relationType")
                visible = xmletree.get_element_attribute_as_boolean(rml_uri, "visible")
                value = xmletree.get_element_text(rml_uri)

                url = metajson_service.create_url(value, preferred, relation_type, None, None, visible)
                if url:
                    urls.append(url)
        if urls:
            result["urls"] = urls
    return result