I need to loop through a GeoJSON file, where for each "feature", find the city where the track started:

```
with open('input.geojson') as f:
    gj = geojson.load(f)

for track in gj['features']:
    #OK
    print track['geometry']['coordinates'][0]

    #How to query Nominatim to find the city that lat,lon belongs to?

    #Next step : edit 'name' in gj

with open('dump.geojson', 'w') as f:
   dump(gj, f, indent=2)

```

Would someone have some code handy?