code: def chat_response():
      return {
          "id": "chatcmpl-abc123",
          "object": "chat.completion",
          "created": 1677858242,
          "model": "gpt-3.5-turbo-0301",
          "usage": {
              "prompt_tokens": 13,
              "completion_tokens": 7,
              "total_tokens": 20,
          },
          "choices": [
              {
                  "message": {
                      "role": "assistant",
                      "content": "\n\nThis is a test!",
                  },
                  "finish_reason": "stop",
                  "index": 0,
              }
          ],
          "headers": {"Content-Type": "application/json"},
      }
  
file_path: mlflow/tests/gateway/providers/test_openai.py
imports: from unittest import mock
  import pytest
  from aiohttp import ClientTimeout
  from fastapi import HTTPException
  from fastapi.encoders import jsonable_encoder
  from pydantic import ValidationError
  from mlflow.exceptions import MlflowException
  from mlflow.gateway.config import OpenAIConfig, RouteConfig
  from mlflow.gateway.constants import MLFLOW_GATEWAY_ROUTE_TIMEOUT_SECONDS
  from mlflow.gateway.providers.openai import OpenAIProvider
  from mlflow.gateway.schemas import chat, completions, embeddings
  from tests.gateway.tools import MockAsyncResponse, mock_http_client
label_desc: Use image node_id 2 for calling a global function with example usage: chat_response() and returns: dict