How to use the rdmo.questions.models.Catalog function in rdmo

def get_form_kwargs(self):
        catalogs = Catalog.objects.filter_current_site().filter_group(self.request.user)

        form_kwargs = super().get_form_kwargs()
        form_kwargs.update({
            'catalogs': catalogs
        })
        return form_kwargs

def import_catalog(element):
    try:
        catalog = Catalog.objects.get(uri=element['uri'])
    except Catalog.DoesNotExist:
        log.info('Catalog not in db. Created with uri %s.', element['uri'])
        catalog = Catalog()

    catalog.uri_prefix = element['uri_prefix'] or ''
    catalog.key = element['key'] or ''
    catalog.comment = element['comment'] or ''

    catalog.order = element['order']

    for lang_code, lang_string, lang_field in get_languages():
        set_lang_field(catalog, 'title', element, lang_code, lang_field)

    try:
        CatalogUniqueKeyValidator(catalog).validate()
    except ValidationError as e:
        log.info('Catalog not saving "%s" due to validation error (%s).', element['uri'], e)
        pass
    else:

Site, on_delete=models.CASCADE,
        verbose_name=_('Site'),
        help_text=_('The site this project belongs to (in a multi site setup).')
    )
    title = models.CharField(
        max_length=256,
        verbose_name=_('Title'),
        help_text=_('The title for this project.')
    )
    description = models.TextField(
        blank=True,
        verbose_name=_('Description'),
        help_text=_('A description for this project (optional).')
    )
    catalog = models.ForeignKey(
        Catalog, related_name='+', on_delete=models.SET_NULL, null=True,
        verbose_name=_('Catalog'),
        help_text=_('The catalog which will be used for this project.')
    )
    tasks = models.ManyToManyField(
        Task, blank=True,
        verbose_name=_('Tasks'),
        help_text=_('The tasks that will be used for this project.')
    )
    views = models.ManyToManyField(
        View, blank=True,
        verbose_name=_('Views'),
        help_text=_('The views that will be used for this project.')
    )

    class Meta:
        ordering = ('title', )

QuestionSetSerializer,
    QuestionSerializer,
    CatalogIndexSerializer,
    SectionIndexSerializer,
    QuestionSetIndexSerializer,
    QuestionIndexSerializer,
    CatalogNestedSerializer,
    SectionNestedSerializer,
    QuestionSetNestedSerializer,
    QuestionNestedSerializer
)


class CatalogViewSet(ModelViewSet):
    permission_classes = (HasModelPermission, )
    queryset = Catalog.objects.all()
    serializer_class = CatalogSerializer

    filter_backends = (DjangoFilterBackend,)
    filter_fields = (
        'uri',
        'key'
    )

    @action(detail=True)
    def nested(self, request, pk):
        queryset = get_object_or_404(Catalog, pk=pk)
        serializer = CatalogNestedSerializer(queryset)
        return Response(serializer.data)

    @action(detail=False)
    def index(self, request):

def handle(self, *args, **options):

        for obj in Condition.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in OptionSet.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in Option.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in AttributeEntity.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in Catalog.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in Section.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in Subsection.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in QuestionEntity.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in Task.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

        for obj in View.objects.all():
            self._set_uri_prefix(obj, options['uri_prefix'])

def import_project(user, root):
    ns_map = get_ns_map(root)

    project = Project()

    project.title = root.find('title').text or ''
    project.description = root.find('description').text or ''
    project.created = root.find('created').text
    project.site = Site.objects.get_current()

    catalog = get_uri(root.find('catalog'), ns_map)

    try:
        project.catalog = Catalog.objects.all().get(uri=catalog)
    except Catalog.DoesNotExist:
        log.info('Catalog not in db. Created with uri %s', catalog)
        project.catalog = Catalog.objects.all().first()

    project.save()

    # add user to project
    membership = Membership(project=project, user=user, role='owner')
    membership.save()

    tasks_node = root.find('tasks')
    if tasks_node is not None:
        for task_node in tasks_node.findall('task'):
            try:
                task_uri = get_uri(task_node, ns_map)
                project.tasks.add(Task.objects.get(uri=task_uri))

def import_section(element):
    try:
        section = Section.objects.get(uri=element['uri'])
    except Section.DoesNotExist:
        log.info('Section not in db. Created with uri %s.', element['uri'])
        section = Section()

    try:
        section.catalog = Catalog.objects.get(uri=element['catalog'])
    except Catalog.DoesNotExist:
        log.info('Catalog not in db. Skipping.')
        return

    section.uri_prefix = element['uri_prefix'] or ''
    section.key = element['key'] or ''
    section.comment = element['comment'] or ''

    section.order = element['order']

    for lang_code, lang_string, lang_field in get_languages():
        set_lang_field(section, 'title', element, lang_code, lang_field)

    try:
        SectionUniquePathValidator(section).validate()
    except ValidationError as e:
        log.info('Section not saving "%s" due to validation error (%s).', element['uri'], e)

def nested(self, request, pk):
        queryset = get_object_or_404(Catalog, pk=pk)
        serializer = CatalogNestedSerializer(queryset)
        return Response(serializer.data)

def first(self, request, pk=None):
        try:
            catalog = Catalog.objects.get(pk=request.GET.get('catalog'))
            questionset = QuestionSet.objects.order_by_catalog(catalog).first()
            serializer = self.get_serializer(questionset)
            return Response(serializer.data)
        except Catalog.DoesNotExist:
            raise NotFound()

def first(self, request, pk=None):
        try:
            catalog = Catalog.objects.get(pk=request.GET.get('catalog'))
            questionset = QuestionSet.objects.order_by_catalog(catalog).first()
            serializer = self.get_serializer(questionset)
            return Response(serializer.data)
        except Catalog.DoesNotExist:
            raise NotFound()