async def start_chat_repl(self) -> None:
        """
        Start a REPL for chatting with the agent.
        """
        if self.query_pipeline is None:
            raise ValueError("query_pipeline is not defined.")
        chat_engine = cast(CondenseQuestionChatEngine, self.chat_engine)
        chat_engine.streaming_chat_repl()

        Start a REPL for chatting with the agent.
        
llama-index-cli/llama_index/cli/rag/base.py