show geometries for both categorical and numerical fields in the same plot - px.choropleth

I am trying to create a US county map (including AK and HI in the bottom corner of the continental map) in plotly. I do not have numerical data for every county. In fact I only have data for 50 counties (approx). I want the map to contain the geometry for the for the counties with not data, so I can plot them in a different color. Otherwise the map is to empty. I tried with add.trace but I could not make it work.

``
import plotly.graph_objs as go
import plotly.express as px
import pandas as pd
from urllib.request import urlopen
import json

with urlopen('https://raw.githubusercontent.com/plotly/datasets/master/geojson-counties-fips.json') as response:
counties = json.load(response)

df = pd.read_csv("https://raw.githubusercontent.com/plotly/datasets/master/fips-unemp-16.csv",
dtype={"fips": str})

df_nodata=df.loc[df.unemp <= 10]

df_nodata['categorical'] = 'no data'

df_data = df.loc[df.unemp > 10]

fig = px.choropleth(df_data,
geojson=counties,
locations=df_data.fips,
color=df_data.unemp,
scope='usa')

fig.add_trace(go.Figure(go.Choroplethmapbox(geojson=counties, locations=df_nodata.fips, z=df_nodata.categorical))
)

fig.show()

``
I am trying to combine the attached

layers.

まず px.choropleth を使った例と、試行した go.Choroplethmapbox trace を再現し、その後、これらのエントリーポイントが地理レイヤーをどのように構成しているかを調べます。結果には、同じ米国のマップ上でデータのある郡とデータのない郡を表示し、データのない郡には異なる色を使用します。