langchain/chat_models/openai.py/ChatOpenAI/_generate
class ChatOpenAI:    def _generate(
        self,
        messages: List[BaseMessage],
        stop: Optional[List[str]] = None,
        run_manager: Optional[CallbackManagerForLLMRun] = None,
    ) -> ChatResult:
        message_dicts, params = self._create_message_dicts(messages, stop)
        if self.streaming:
            inner_completion = ""
            role = "assistant"
            params["stream"] = True
            for stream_resp in self.completion_with_retry(
                messages=message_dicts, **params
            ):
                role = stream_resp["choices"][0]["delta"].get("role", role)
                token = stream_resp["choices"][0]["delta"].get("content", "")
                inner_completion += token
                if run_manager:
                    run_manager.on_llm_new_token(token)
            message = _convert_dict_to_message(
                {"content": inner_completion, "role": role}
            )
            return ChatResult(generations=[ChatGeneration(message=message)])
        response = self.completion_with_retry(messages=message_dicts, **params)
        return self._create_chat_result(response)