code: def test_customprompt_together_ai():
      try:
          litellm.set_verbose = False
          litellm.num_retries = 0
          print("in test_customprompt_together_ai")
          print(litellm.success_callback)
          print(litellm._async_success_callback)
          response = completion(
              model="together_ai/mistralai/Mistral-7B-Instruct-v0.1",
              messages=messages,
              roles={
                  "system": {
                      "pre_message": "<|im_start|>system\n",
                      "post_message": "<|im_end|>",
                  },
                  "assistant": {
                      "pre_message": "<|im_start|>assistant\n",
                      "post_message": "<|im_end|>",
                  },
                  "user": {
                      "pre_message": "<|im_start|>user\n",
                      "post_message": "<|im_end|>",
                  },
              },
          )
          print(response)
      except litellm.exceptions.Timeout as e:
          print(f"Timeout Error")
          pass
      except Exception as e:
          print(f"ERROR TYPE {type(e)}")
          pytest.fail(f"Error occurred: {e}")
  
imports: import sys, os
  import traceback
  from dotenv import load_dotenv
  import os, io
  import pytest
  import litellm
  from litellm import embedding, completion, completion_cost, Timeout
  from litellm import RateLimitError
  import openai
label_desc: Use image node_id 39 for calling a global function with example usage: test_customprompt_together_ai() without return types