How to make data for a new chorophleth map?

I checked Dash’s new chorophth map here.

I have a map of Korea’s administrative region(geojson, shape file), and would like to make data corresponding to the “location” of “Carto base map: no token needs.”

import pandas as pd
unemp = pd.read_csv("",
                   dtype={"fips": str})

I want to know in detail what the above code means.
I understood importing json files to create maps, but I can’t understand the “unemp” variable.
I want to get more information about “unemp.fips” and “unemp.unemp.”
Thank you for the endless development of the dash.

@suhyun, In the example above umemp is a dataframe with two columns. unemp.fips is one of the columns and each element in that column corresponds to an "id" attribute in your geojson file. The other column is unemp.unemp which represents the unemployment rate for the counties. Each row of this dataframe represents the id and unemployment rate of a single county.

For example, I copied the geojson object for McPhearson county here:

		"type": "Feature",
		"properties": {
			"GEO_ID": "0500000US31117",
			"STATE": "31",
			"COUNTY": "117",
			"NAME": "McPherson",
			"LSAD": "County",
			"CENSUSAREA": 858.976
		"geometry": {
			"type": "Polygon",
			"coordinates": [
					[-101.269695, 41.394934],
					[-101.40726, 41.395416],
					[-101.406466, 41.7432],
					[-100.842459, 41.740404],
					[-100.711711, 41.739761],
					[-100.713132, 41.394575],
					[-100.713243, 41.393511],
					[-101.269695, 41.394934]
		"id": "31117"

It has an "id" equal to 31117 and by looking up the row where unemp.fips == 31117, I can see that there is an unemployment rate of 2.4. So basically, the locations attribute in the trace maps the z attribute with the same index to a polygon defined in the geojson file via the "id" attribute.