Choropleth map is not getting generated from mapboxmap

I am able to generate the choropleth map using go.Choroplethmapbox in jupyter notebook. But when I try this in dash app, I am getting nothin. I am updating graph through call back. Please help me to get the choropleth map. Call back code is given below:

    Output('example-graph', 'figure'),
def update_fig(z_value):        

    fig = go.Figure([go.Choroplethmapbox(geojson=j_file, locations=df.area_code, z=df.total_count,

                                    colorscale="Viridis", zmin=0, zmax=150,

                                    marker_opacity=0.5, marker_line_width=0)])        



                        mapbox_zoom=z_value, mapbox_center = {"lat":52.480271148513935, "lon":-1.90887451171875})

    return fig

I encountered the same problem, figure is generated correctly just somehow not displayed in a dcc.Graph object.