Fix OpenAI deprecation warning

[digitalronin]

Whenever I run promptimize, using the gpt-3.5-turbo model, I get the following deprecation warning:

~/.pyenv/versions/myenv/lib/python3.10/site-packages/langchain/llms/openai.py:172: UserWarning: You are trying to use a chat model. This way of initializing it is no longer supported. Instead, please use: `from langchain.chat_models import ChatOpenAI`

I think this relates to this langchain discussion thread, but when I try to implement the suggested fix, I get a different error:

~/.pyenv/versions/myenv/lib/python3.10/site-packages/langchain/callbacks/manager.py", line 297, in _handle_event
    getattr(handler, event_name)(*args, **kwargs)
  File "~/.pyenv/versions/myenv/lib/python3.10/site-packages/langchain/callbacks/base.py", line 167, in on_chat_model_start
    raise NotImplementedError(
NotImplementedError: OpenAICallbackHandler does not implement `on_chat_model_start`

[ybsun0215]

Hello, i get the following error when running the code, presumably because the model is not specified.

"pydantic.errors.PydanticUserError: A non-annotated attribute was detected: lookup_index = 0. All model fields require a type annotation; if lookup_index is not meant to be a field, you may be able to resolve this error by annotating it as a ClassVar or updating model_config['ignored_types']."

where can I set up the model?