How to use the xandikos.davcommon.get_properties_with_data function in xandikos

tz = get_calendar_timezone(base_resource)

        def filter_fn(cls):
            return parse_filter(filter_el, cls(tz))

        def members(collection):
            return itertools.chain(
                collection.calendar_query(filter_fn),
                collection.subcollections())

        async for (href, resource) in webdav.traverse_resource(
                base_resource, base_href, depth,
                members=members):
            # Ideally traverse_resource would only return the right things.
            if getattr(resource, 'content_type', None) == 'text/calendar':
                propstat = davcommon.get_properties_with_data(
                    self.data_property, href, resource, properties, environ,
                    requested)
                yield webdav.Status(
                    href, '200 OK', propstat=[s async for s in propstat])

try:
                nresults = int(nresults_el.text)
            except ValueError:
                raise webdav.BadRequestError(
                    'nresults not a number')
        else:
            nresults = None

        i = 0
        async for (href, resource) in webdav.traverse_resource(
                base_resource, base_href, depth):
            if not apply_filter(filter_el, resource):
                continue
            if nresults is not None and i >= nresults:
                break
            propstat = davcommon.get_properties_with_data(
                self.data_property, href, resource, properties, environ,
                requested)
            yield webdav.Status(
                href, '200 OK', propstat=[s async for s in propstat])
            i += 1