How to use the neuroglancer.ViewerState function in neuroglancer

def display_split_result(graph, agglo_id, cur_eqs, supervoxel_map, split_seeds, image_url,
                         segmentation_url):

    agglo_members = set(graph.get_agglo_members(agglo_id))
    state = neuroglancer.ViewerState()
    state.layers.append(name='image', layer=neuroglancer.ImageLayer(source=image_url))
    state.layers.append(
        name='original',
        layer=neuroglancer.SegmentationLayer(
            source=segmentation_url,
            segments=agglo_members,
        ),
        visible=False,
    )
    state.layers.append(
        name='isolated-supervoxels',
        layer=neuroglancer.SegmentationLayer(
            source=segmentation_url,
            segments=set(x for x, seeds in six.viewitems(supervoxel_map) if len(seeds) > 1),
        ),
        visible=False,

def set_state_index(self, index):
        self._grab_viewer_state()
        self.state_index = index
        if index is None:
            self.viewer.set_state(neuroglancer.ViewerState())
        else:
            self.viewer.set_state(self.states[index])
            other_ids = self.other_state_segment_ids
            other_ids.clear()
            other_ids[0] = -1
            for i, state in enumerate(self.states):
                if i == self.state_index:
                    continue
                for x in self.get_state_segment_ids(state):
                    other_ids[x] = i
        self.update_message()

def load(self):
        if not os.path.exists(self.filename):
            return False
        self.state_index = None

        with open(self.filename, 'r') as f:
            loaded_state = decode_json(f.read())
        self.states = [neuroglancer.ViewerState(x) for x in loaded_state['states']]
        self.set_state_index(loaded_state['state_index'])
        return True

def add_segments_from_state(self, base_state):
        if isinstance(base_state, basestring):
            base_state = neuroglancer.parse_url(base_state)
        elif isinstance(base_state, dict):
            base_state = neuroglancer.ViewerState(base_state)

        segment_ids = self.get_state_segment_ids(base_state)

        existing_segment_ids = self.get_existing_segment_ids()

        for segment_id in segment_ids:
            if segment_id in existing_segment_ids:
                print('Skipping redundant segment id %d' % segment_id)
                continue
            self.states.append(self.make_initial_state(segment_id, base_state))

        if self.state_index is None:
            self.next_state()