code: def test_user_agent_custom(self):
      geocoder = GeoNames(
          username="DUMMYUSER_NORBERT", user_agent="my_user_agent/1.0"
      )
      assert geocoder.headers["User-Agent"] == "my_user_agent/1.0"
  
file_path: geopy/test/geocoders/geonames.py
imports: import uuid
  import pytest
  from geopy import Point
  from geopy.exc import GeocoderAuthenticationFailure, GeocoderQueryError
  from geopy.geocoders import GeoNames
  from test.geocoders.util import BaseTestGeocoder, env
label_desc: Use image node_id 1 for calling the TestUnitGeoNames obj's underlying member method code with example usage: obj.test_user_agent_custom() without return types