code: def test_deployment_warning_config(admin_client):
      warn_text = "webserver.warn_deployment_exposure"
      admin_client.get("/robots.txt", follow_redirects=True)
      resp = admin_client.get("", follow_redirects=True)
      assert warn_text in resp.data.decode("utf-8")
  
      with conf_vars(
          {("webserver", "warn_deployment_exposure"): "False"}
      ):
          admin_client.get("/robots.txt", follow_redirects=True)
          resp = admin_client.get("/robots.txt", follow_redirects=True)
          assert warn_text not in resp.data.decode("utf-8")
  
imports: from __future__ import annotations
  import pytest
  from tests.test_utils.config import conf_vars
label_desc: Use image node_id 2 for calling a global function with example usage: test_deployment_warning_config(admin_client) without return types