How to use the gpxpy.gpxfield.GPXComplexField function in gpxpy

class GPX:
    gpx_10_fields = [
            mod_gpxfield.GPXField('version', attribute=True),
            mod_gpxfield.GPXField('creator', attribute=True),
            mod_gpxfield.GPXField('name'),
            mod_gpxfield.GPXField('description', 'desc'),
            mod_gpxfield.GPXField('author_name', 'author'),
            mod_gpxfield.GPXField('author_email', 'email'),
            mod_gpxfield.GPXField('link', 'url'),
            mod_gpxfield.GPXField('link_text', 'urlname'),
            mod_gpxfield.GPXField('time', type=mod_gpxfield.TIME_TYPE),
            mod_gpxfield.GPXField('keywords'),
            mod_gpxfield.GPXComplexField('bounds', classs=GPXBounds),
            mod_gpxfield.GPXComplexField('waypoints', classs=GPXWaypoint, tag='wpt', is_list=True),
            mod_gpxfield.GPXComplexField('routes', classs=GPXRoute, tag='rte', is_list=True),
            mod_gpxfield.GPXComplexField('tracks', classs=GPXTrack, tag='trk', is_list=True),
    ]
    # Text fields serialize as empty container tags, dependents are
    # are listed after as 'tag:dep1:dep2:dep3'. If no dependents are
    # listed, it will always serialize. The container is closed with
    # '/tag'. Required dependents are preceded by an @. If a required
    # dependent is empty, nothing in the container will serialize. The
    # format is 'tag:@dep2'. No optional dependents need to be listed.
    # Extensions not yet supported
    gpx_11_fields = [
            mod_gpxfield.GPXField('version', attribute=True),
            mod_gpxfield.GPXField('creator', attribute=True),
            'metadata:name:description:author_name:author_email:author_link:copyright_author:copyright_year:copyright_license:link:time:keywords:bounds',
                mod_gpxfield.GPXField('name', 'name'),
                mod_gpxfield.GPXField('description', 'desc'),
                'author:author_name:author_email:author_link',
                    mod_gpxfield.GPXField('author_name', 'name'),

mod_gpxfield.GPXField('author_link_type', tag='type'),
                    '/link',
                '/author',
                'copyright:copyright_author:copyright_year:copyright_license',
                    mod_gpxfield.GPXField('copyright_author', attribute='author'),
                    mod_gpxfield.GPXField('copyright_year', tag='year'),
                    mod_gpxfield.GPXField('copyright_license', tag='license'),
                '/copyright',
                'link:@link',
                    mod_gpxfield.GPXField('link', attribute='href'),
                    mod_gpxfield.GPXField('link_text', tag='text'),
                    mod_gpxfield.GPXField('link_type', tag='type'),
                '/link',
                mod_gpxfield.GPXField('time', type=mod_gpxfield.TIME_TYPE),
                mod_gpxfield.GPXField('keywords'),
                mod_gpxfield.GPXComplexField('bounds', classs=GPXBounds),
                mod_gpxfield.GPXExtensionsField('metadata_extensions', tag='extensions'),
            '/metadata',
            mod_gpxfield.GPXComplexField('waypoints', classs=GPXWaypoint, tag='wpt', is_list=True),
            mod_gpxfield.GPXComplexField('routes', classs=GPXRoute, tag='rte', is_list=True),
            mod_gpxfield.GPXComplexField('tracks', classs=GPXTrack, tag='trk', is_list=True),
            mod_gpxfield.GPXExtensionsField('extensions', is_list=True),
    ]

    __slots__ = ('version', 'creator', 'name', 'description', 'author_name',
                 'author_email', 'link', 'link_text', 'time', 'keywords',
                 'bounds', 'waypoints', 'routes', 'tracks', 'author_link',
                 'author_link_text', 'author_link_type', 'copyright_author',
                 'copyright_year', 'copyright_license', 'link_type',
                 'metadata_extensions', 'extensions', 'nsmap',
                 'schema_locations')

]
    gpx_11_fields = [
            # See GPX for text field description
            mod_gpxfield.GPXField('name'),
            mod_gpxfield.GPXField('comment', 'cmt'),
            mod_gpxfield.GPXField('description', 'desc'),
            mod_gpxfield.GPXField('source', 'src'),
            'link:@link',
                mod_gpxfield.GPXField('link', attribute='href'),
                mod_gpxfield.GPXField('link_text', tag='text'),
                mod_gpxfield.GPXField('link_type', tag='type'),
            '/link',
            mod_gpxfield.GPXField('number', type=mod_gpxfield.INT_TYPE),
            mod_gpxfield.GPXField('type'),
            mod_gpxfield.GPXExtensionsField('extensions', is_list=True),
            mod_gpxfield.GPXComplexField('segments', tag='trkseg', classs=GPXTrackSegment, is_list=True),
    ]

    __slots__ = ('name', 'comment', 'description', 'source', 'link',
                 'link_text', 'number', 'segments', 'link_type', 'type',
                 'extensions')

    def __init__(self, name=None, description=None, number=None):
        self.name = name
        self.comment = None
        self.description = description
        self.source = None
        self.link = None
        self.link_text = None
        self.number = number
        self.segments = []
        self.link_type = None

mod_gpxfield.GPXField('copyright_author', attribute='author'),
                    mod_gpxfield.GPXField('copyright_year', tag='year'),
                    mod_gpxfield.GPXField('copyright_license', tag='license'),
                '/copyright',
                'link:@link',
                    mod_gpxfield.GPXField('link', attribute='href'),
                    mod_gpxfield.GPXField('link_text', tag='text'),
                    mod_gpxfield.GPXField('link_type', tag='type'),
                '/link',
                mod_gpxfield.GPXField('time', type=mod_gpxfield.TIME_TYPE),
                mod_gpxfield.GPXField('keywords'),
                mod_gpxfield.GPXComplexField('bounds', classs=GPXBounds),
                mod_gpxfield.GPXExtensionsField('metadata_extensions', tag='extensions'),
            '/metadata',
            mod_gpxfield.GPXComplexField('waypoints', classs=GPXWaypoint, tag='wpt', is_list=True),
            mod_gpxfield.GPXComplexField('routes', classs=GPXRoute, tag='rte', is_list=True),
            mod_gpxfield.GPXComplexField('tracks', classs=GPXTrack, tag='trk', is_list=True),
            mod_gpxfield.GPXExtensionsField('extensions', is_list=True),
    ]

    __slots__ = ('version', 'creator', 'name', 'description', 'author_name',
                 'author_email', 'link', 'link_text', 'time', 'keywords',
                 'bounds', 'waypoints', 'routes', 'tracks', 'author_link',
                 'author_link_text', 'author_link_type', 'copyright_author',
                 'copyright_year', 'copyright_license', 'link_type',
                 'metadata_extensions', 'extensions', 'nsmap',
                 'schema_locations')

    def __init__(self):
        self.version = None
        self.creator = None
        self.name = None

class GPX:
    gpx_10_fields = [
            mod_gpxfield.GPXField('version', attribute=True),
            mod_gpxfield.GPXField('creator', attribute=True),
            mod_gpxfield.GPXField('name'),
            mod_gpxfield.GPXField('description', 'desc'),
            mod_gpxfield.GPXField('author_name', 'author'),
            mod_gpxfield.GPXField('author_email', 'email'),
            mod_gpxfield.GPXField('link', 'url'),
            mod_gpxfield.GPXField('link_text', 'urlname'),
            mod_gpxfield.GPXField('time', type=mod_gpxfield.TIME_TYPE),
            mod_gpxfield.GPXField('keywords'),
            mod_gpxfield.GPXComplexField('bounds', classs=GPXBounds),
            mod_gpxfield.GPXComplexField('waypoints', classs=GPXWaypoint, tag='wpt', is_list=True),
            mod_gpxfield.GPXComplexField('routes', classs=GPXRoute, tag='rte', is_list=True),
            mod_gpxfield.GPXComplexField('tracks', classs=GPXTrack, tag='trk', is_list=True),
    ]
    # Text fields serialize as empty container tags, dependents are
    # are listed after as 'tag:dep1:dep2:dep3'. If no dependents are
    # listed, it will always serialize. The container is closed with
    # '/tag'. Required dependents are preceded by an @. If a required
    # dependent is empty, nothing in the container will serialize. The
    # format is 'tag:@dep2'. No optional dependents need to be listed.
    # Extensions not yet supported
    gpx_11_fields = [
            mod_gpxfield.GPXField('version', attribute=True),
            mod_gpxfield.GPXField('creator', attribute=True),
            'metadata:name:description:author_name:author_email:author_link:copyright_author:copyright_year:copyright_license:link:time:keywords:bounds',
                mod_gpxfield.GPXField('name', 'name'),
                mod_gpxfield.GPXField('description', 'desc'),

return 'GPXTrackSegment(points=[%s])' % ('...' if self.points else '')

    def clone(self):
        return mod_copy.deepcopy(self)


class GPXTrack:
    gpx_10_fields = [
            mod_gpxfield.GPXField('name'),
            mod_gpxfield.GPXField('comment', 'cmt'),
            mod_gpxfield.GPXField('description', 'desc'),
            mod_gpxfield.GPXField('source', 'src'),
            mod_gpxfield.GPXField('link', 'url'),
            mod_gpxfield.GPXField('link_text', 'urlname'),
            mod_gpxfield.GPXField('number', type=mod_gpxfield.INT_TYPE),
            mod_gpxfield.GPXComplexField('segments', tag='trkseg', classs=GPXTrackSegment, is_list=True),
    ]
    gpx_11_fields = [
            # See GPX for text field description
            mod_gpxfield.GPXField('name'),
            mod_gpxfield.GPXField('comment', 'cmt'),
            mod_gpxfield.GPXField('description', 'desc'),
            mod_gpxfield.GPXField('source', 'src'),
            'link:@link',
                mod_gpxfield.GPXField('link', attribute='href'),
                mod_gpxfield.GPXField('link_text', tag='text'),
                mod_gpxfield.GPXField('link_type', tag='type'),
            '/link',
            mod_gpxfield.GPXField('number', type=mod_gpxfield.INT_TYPE),
            mod_gpxfield.GPXField('type'),
            mod_gpxfield.GPXExtensionsField('extensions', is_list=True),
            mod_gpxfield.GPXComplexField('segments', tag='trkseg', classs=GPXTrackSegment, is_list=True),

def remove_time(self):
        """ Will remove time metadata. """
        self.time = None


class GPXRoute:
    gpx_10_fields = [
            mod_gpxfield.GPXField('name'),
            mod_gpxfield.GPXField('comment', 'cmt'),
            mod_gpxfield.GPXField('description', 'desc'),
            mod_gpxfield.GPXField('source', 'src'),
            mod_gpxfield.GPXField('link', 'url'),
            mod_gpxfield.GPXField('link_text', 'urlname'),
            mod_gpxfield.GPXField('number', type=mod_gpxfield.INT_TYPE),
            mod_gpxfield.GPXComplexField('points', tag='rtept', classs=GPXRoutePoint, is_list=True),
    ]
    gpx_11_fields = [
            # See GPX for description of text fields
            mod_gpxfield.GPXField('name'),
            mod_gpxfield.GPXField('comment', 'cmt'),
            mod_gpxfield.GPXField('description', 'desc'),
            mod_gpxfield.GPXField('source', 'src'),
            'link:@link',
                mod_gpxfield.GPXField('link', attribute='href'),
                mod_gpxfield.GPXField('link_text', tag='text'),
                mod_gpxfield.GPXField('link_type', tag='type'),
            '/link',
            mod_gpxfield.GPXField('number', type=mod_gpxfield.INT_TYPE),
            mod_gpxfield.GPXField('type'),
            mod_gpxfield.GPXExtensionsField('extensions', is_list=True),
            mod_gpxfield.GPXComplexField('points', tag='rtept', classs=GPXRoutePoint, is_list=True),