code: def validate_environment(model: str):
      global llm
      try:
          from vllm import LLM, SamplingParams  # type: ignore
  
          if llm is None:
              llm = LLM(model=model)
          return llm, SamplingParams
      except Exception as e:
          raise VLLMError(status_code=0, message=str(e))
  
file_path: litellm/litellm/llms/vllm.py
imports: import os
  import json
  from enum import Enum
  import requests
  import time, httpx
  from typing import Callable, Any
  from litellm.utils import ModelResponse, Usage
  from .prompt_templates.factory import prompt_factory, custom_prompt
label_desc: Use image node_id 1 for calling a global function with example usage: validate_environment(model) and returns: llm,  SamplingParams