def __init__(self):
        """Initialize the chat service with OpenAI client."""
        if not settings.OPENAI_API_KEY:
            logger.warning("OPENAI_API_KEY is not set in environment variables")
            self.client = None
        else:
            self.client = AsyncOpenAI(
                api_key=settings.OPENAI_API_KEY,
            )
Initialize the chat service with OpenAI client.
backend/airweave/core/chat_service.py