code: def _is_chat_model_engine(self, model_engine: str):
      return model_engine.startswith(
          "gpt-3.5"
      ) or model_engine.startswith("gpt-4")
  
file_path: H2O/h2o_hf/helm/src/helm/proxy/clients/openai_client.py
imports: from dataclasses import replace, asdict
  from typing import Any, Dict, List, Optional, cast
  import openai
  import tiktoken
  from helm.common.cache import Cache, CacheConfig
  from helm.common.request import Request, RequestResult, Sequence, Token
  from helm.common.tokenization_request import TokenizationRequest, TokenizationRequestResult, DecodeRequest, DecodeRequestResult, TokenizationToken
  from .client import Client, truncate_sequence, wrap_request_time
  from .chat_gpt_client import ChatGPTClient
label_desc: Use image node_id 2 for calling the OpenAIClient obj's underlying member method code with example usage: obj._is_chat_model_engine(model_engine) and returns: unknown