code: def test_fastapi_multiple_headers(serve_instance):
      # https://fastapi.tiangolo.com/advanced/response-cookies/
      app = FastAPI()
  
      @app.get("/")
      def func(resp: Response):
          resp.set_cookie(key="a", value="b")
          resp.set_cookie(key="c", value="d")
          return "hello"
  
      @serve.deployment
      @serve.ingress(app)
      class FastAPIApp:
          pass
  
      serve.run(FastAPIApp.bind())
  
      resp = requests.get("http://localhost:8000/")
      assert resp.cookies.get_dict() == {"a": "b", "c": "d"}
  
imports: import inspect
  import tempfile
  import time
  from typing import Any, List, Optional
  import pytest
  import requests
  import starlette.responses
  from fastapi import APIRouter, BackgroundTasks, Cookie, Depends, FastAPI, Header, Query, Request, Response
  from fastapi.middleware.cors import CORSMiddleware
  from fastapi.responses import JSONResponse
  from pydantic import BaseModel, Field
  from starlette.applications import Starlette
  from starlette.routing import Route
  import ray
  from ray import serve
  from ray._private.test_utils import SignalActor, wait_for_condition
  from ray.exceptions import GetTimeoutError
  from ray.serve._private.client import ServeControllerClient
  from ray.serve._private.constants import SERVE_DEFAULT_APP_NAME
  from ray.serve._private.http_util import make_fastapi_class_based_view
  from ray.serve._private.utils import DEFAULT
  from ray.serve.exceptions import RayServeException
  from ray.serve.handle import DeploymentHandle
label_desc: Use image node_id 12 for calling a global function with example usage: test_fastapi_multiple_headers(serve_instance) and returns: str