Default model is `ERNIE-Bot-turbo`,
    currently supported models are `ERNIE-Bot-turbo`, `ERNIE-Bot`, `ERNIE-Bot-8K`,
    `ERNIE-Bot-4`, `ERNIE-Bot-turbo-AI`.
    Example:
        .. code-block:: python
            from langchain_community.chat_models import ErnieBotChat
            chat = ErnieBotChat(model_name='ERNIE-Bot')
    Deprecated Note:
    Please use `QianfanChatEndpoint` instead of this class.
    `QianfanChatEndpoint` is a more suitable choice for production.
    Always test your code after changing to `QianfanChatEndpoint`.
    Example of `QianfanChatEndpoint`:
        .. code-block:: python
            from langchain_community.chat_models import QianfanChatEndpoint
            qianfan_chat = QianfanChatEndpoint(model="ERNIE-Bot",
                endpoint="your_endpoint", qianfan_ak="your_ak", qianfan_sk="your_sk")
    """
    ernie_api_base: Optional[str] = None
    """Baidu application custom endpoints"""
    ernie_client_id: Optional[str] = None
    """Baidu application client id"""
    ernie_client_secret: Optional[str] = None
    """Baidu application client secret"""
    access_token: Optional[str] = None
    """access token is generated by client id and client secret, 
    setting this value directly will cause an error"""
    model_name: str = "ERNIE-Bot-turbo"
    """model name of ernie, default is `ERNIE-Bot-turbo`.
      Currently supported `ERNIE-Bot-turbo`, `ERNIE-Bot`"""
    system: Optional[str] = None