How to use the jupyter.iclientpy._version.EXTENSION_VERSION function in jupyter

from ipywidgets import Layout, IntRangeSlider, ColorPicker, IntSlider, FloatSlider
import ipywidgets as widgets
import pandas as pd
import geojson
import os
import math
from .._version import EXTENSION_VERSION


class HeatLayer(Layer):
    _view_name = Unicode("SuperMapHeatLayerView").tag(sync=True)
    _model_name = Unicode("SuperMapHeatLayerModel").tag(sync=True)
    _view_module = Unicode("iclientpy").tag(sync=True)
    _model_module = Unicode("iclientpy").tag(sync=True)
    _view_module_version = Unicode(EXTENSION_VERSION).tag(sync=True)
    _model_module_version = Unicode(EXTENSION_VERSION).tag(sync=True)

    heat_points = List([]).tag(sync=True)

    @validate('heat_points')
    def _validate_heat_points(self, proposal):
        if (proposal['value'] is None):
            raise Exception("error data")
        self.max = max(dt[2] for dt in self.heat_points)
        return proposal['value']

    radius = Int(25).tag(sync=True, o=True)
    min_opacity = Float(0.05).tag(sync=True, o=True)
    max_zoom = Int().tag(sync=True, o=True)
    max = Float(1.0).tag(sync=True, o=True)
    blur = Int(15).tag(sync=True, o=True)
    gradient = Dict().tag(sync=True, o=True)

def __init__(self, name, data, **kwargs):
        super(RankSymbolThemeLayer, self).__init__(**kwargs)
        self.name = name
        self.sdata = data


class MapView(Map):
    @default('layout')
    def _default_layout(self):
        return Layout(height='500px', align_self='stretch')

    _view_name = Unicode("SuperMapMapView").tag(sync=True)
    _model_name = Unicode("SuperMapMapModel").tag(sync=True)
    _view_module = Unicode("iclientpy").tag(sync=True)
    _model_module = Unicode("iclientpy").tag(sync=True)
    _view_module_version = Unicode(EXTENSION_VERSION).tag(sync=True)
    _model_module_version = Unicode(EXTENSION_VERSION).tag(sync=True)

    center = List([34.5393842300, 108.9282514100]).tag(sync=True, o=True)
    zoom = Int(15).tag(sync=True, o=True)
    crs = Unicode('EPSG3857').tag(sync=True, o=True)
    prefer_canvas = Bool(False).tag(sync=True, o=True)

    @default('default_tiles')
    def _default_tiles(self):
        return CloudTileLayer()


def load_geojson_data():
    with open(os.path.join(os.path.dirname(os.path.abspath(__file__)), "chinageojson.json"), 'r',
              encoding='utf-8') as geoJsonFile:
        return geojson.load(geoJsonFile)

from traitlets import Instance
from traitlets import validate
from traitlets import Float
from ._version import EXTENSION_VERSION


class Layer(Widget):
    """
    :type _map: Map
    """
    _view_name = Unicode("SuperMapLayerView").tag(sync=True)
    _model_name = Unicode("SuperMapLayerModel").tag(sync=True)
    _view_module = Unicode("iclientpy").tag(sync=True)
    _model_module = Unicode("iclientpy").tag(sync=True)
    _view_module_version = Unicode(EXTENSION_VERSION).tag(sync=True)
    _model_module_version = Unicode(EXTENSION_VERSION).tag(sync=True)

    _map = None
    options = List(trait=Unicode).tag(sync=True)

    @default("options")
    def _default_options(self):
        return [name for name in self.traits(o=True)]

    visibility = Bool(False).tag(sync=True)

    @observe('visibility')
    def _update_visibility(self, change):
        old = change['old']
        new = change['new']
        if self._map is None:
            raise Exception("no map")

def remove_markers(self):
        self.markers = ()


# @register
class Map(DOMWidget):
    @default('layout')
    def _default_layout(self):
        return Layout(height='400px', align_self='stretch')

    _view_name = Unicode('SuperMapMapView').tag(sync=True)
    _model_name = Unicode('SuperMapMapModel').tag(sync=True)
    _view_module = Unicode('iclientpy').tag(sync=True)
    _model_module = Unicode('iclientpy').tag(sync=True)
    _view_module_version = Unicode(EXTENSION_VERSION).tag(sync=True)
    _model_module_version = Unicode(EXTENSION_VERSION).tag(sync=True)

    # center = List(trait=Float).tag(sync=True)

    layers = Tuple(trait=Instance(Layer)).tag(sync=True, **widget_serialization)
    layer_ids = List()

    @validate('layers')
    def _validate_layers(self, proposal):
        self.layer_ids = [l.model_id for l in proposal['value']]
        # if len(set(self.layer_ids) != len(self.layer_ids)):
        #     raise Exception('duplicate layer detected')
        return proposal['value']

    def add_layer(self, layer):
        """
        :type layer:Layer