Add_choropleth_mapbox throwing "Polygon is not json serialisable"

📊 Plotly Python
1

Hi all,
I am having a problem with choropleth_mapbox in python. I can easily make a new choropleth_mapboy figure as follows

import geopandas as gpd
import requests
import plotly_express as px
from shapely.geometry import Point

# import data
data = json.loads(requests.get("http://drive.google.com/uc?id=1ex0kKZgEuhF6-92HyKLW8J1U0r_gxmDM").json())
gdf = gpd.GeoDataFrame.from_features(data["features"]).set_geometry("geometry")

# create new choropleth_mapbox
fig=px.choropleth_mapbox( gdf,
                           geojson=gdf.geometry,
                           locations=gdf.index,
                           color="dummy",
                           center={"lon": gdf.iat[0,0].centroid.x, "lat":gdf.iat[0,0].centroid.y},
                           mapbox_style="carto-darkmatter",
                           color_continuous_scale=blues,
                           zoom=13.5
    )

and fig.show() displays the figure exactly as expected.

But if I create a figure first:

# create figure first
dummy_df = gpd.GeoDataFrame({"geometry":[Point(7.9797197,47.32547143)], "dummy":[1]})

fig=px.choropleth_mapbox( dummy_df,
                           geojson=dummy_df.geometry,
                           locations=dummy_df.index,
                           color="dummy",
                           center={"lon": gdf.iat[0,0].centroid.x, "lat":gdf.iat[0,0].centroid.y},
                           mapbox_style="carto-darkmatter",
                           color_continuous_scale=blues,
                           zoom=13.5
    )
fig.show()

and then add the layer as follows:

fig.add_choroplethmapbox(geojson=gdf.geometry, locations=gdf.index)

I get a TypeError “object of type polygon is not JSON serialisable”

What am I doing wrong?

I have also tried add_trace(px.choropleth_mapbox())

but this throws a different error.