code: def validate_last_format(chunk):
      assert isinstance(
          chunk, ModelResponse
      ), "Chunk should be a dictionary."
      assert isinstance(chunk["id"], str), "'id' should be a string."
      assert isinstance(
          chunk["object"], str
      ), "'object' should be a string."
      assert isinstance(
          chunk["created"], int
      ), "'created' should be an integer."
      assert isinstance(
          chunk["model"], str
      ), "'model' should be a string."
      assert isinstance(
          chunk["choices"], list
      ), "'choices' should be a list."
  
      for choice in chunk["choices"]:
          assert isinstance(
              choice["index"], int
          ), "'index' should be an integer."
          assert isinstance(
              choice["finish_reason"], str
          ), "'finish_reason' should be a string."
  
imports: import sys, os, asyncio
  import traceback
  import time, pytest
  from dotenv import load_dotenv
  import litellm
  from litellm import completion, acompletion, AuthenticationError, BadRequestError, RateLimitError, ModelResponse
label_desc: Use image node_id 4 for calling a global function with example usage: validate_last_format(chunk) without return types