code: def test_user_agent_custom(self):
      geocoder = Geokeo(
          api_key="DUMMYKEY1234", user_agent="my_user_agent/1.0"
      )
      assert geocoder.headers["User-Agent"] == "my_user_agent/1.0"
  
file_path: geopy/test/geocoders/geokeo.py
imports: import pytest
  from geopy.geocoders import Geokeo
  from geopy.point import Point
  from test.geocoders.util import BaseTestGeocoder, env
label_desc: Use image node_id 1 for calling the TestUnitGeokeo obj's underlying member method code with example usage: obj.test_user_agent_custom() without return types