code: def test_img_gen(client_no_auth):
      global headers
      from litellm.proxy.proxy_server import user_custom_auth
  
      try:
          test_data = {
              "model": "dall-e-3",
              "prompt": "A cute baby sea otter",
              "n": 1,
              "size": "1024x1024",
          }
  
          response = client_no_auth.post(
              "/v1/images/generations", json=test_data
          )
  
          assert response.status_code == 200
          result = response.json()
          print(len(result["data"][0]["url"]))
          assert len(result["data"][0]["url"]) > 10
      except Exception as e:
          pytest.fail(
              f"LiteLLM Proxy test failed. Exception - {str(e)}"
          )
  
imports: import sys, os
  import traceback
  from dotenv import load_dotenv
  import os, io
  import pytest, logging, asyncio
  import litellm
  from litellm import embedding, completion, completion_cost, Timeout
  from litellm import RateLimitError
  from fastapi.testclient import TestClient
  from fastapi import FastAPI
  from litellm.proxy.proxy_server import router, save_worker_config, initialize
  from litellm.integrations.custom_logger import CustomLogger
  from litellm.proxy.proxy_server import ProxyConfig
label_desc: Use image node_id 7 for calling a global function with example usage: test_img_gen(client_no_auth) without return types