langchain: 'NoneType' object is not iterable

Question

    async def get_response(self, messages, model):
        try:
            memory = self.memory
            llm = ChatOllama(model=model)
            config = {"configurable": {"thread_id": "abc123"}}
            prompt = ChatPromptTemplate.from_messages(
                [
                    ("system", "You are a helpful assistant"),
                    MessagesPlaceholder("chat_history", optional=True),
                    ("user", "{input}"),
                    MessagesPlaceholder("agent_scratchpad"),
                ]
            )
            agent = create_openai_functions_agent(llm=llm, tools=self.tools, prompt=prompt)
            agent_executor = AgentExecutor(agent=agent, tools=self.tools)

            # Extract the user input from the messages
            user_input = next((message["content"] for message in messages if message["role"] == "user"), "")

            # Wrap the list of messages in a dictionary and include the user input
            formatted_input = {
                "messages": [{"role": message["role"], "content": message["content"]} for message in messages],
                "input": user_input
            }
            response = await agent_executor.ainvoke(formatted_input)

            if response is None:
                logging.error("Received None response from ainvoke")
                return "Error: No response received from the agent."

            # Check if the response includes intermediate steps
            if isinstance(response, dict):
                # Attempt to get intermediate steps if they exist
                intermediate_steps = response.get('intermediate_steps', None)
                final_answer = response.get('final_answer', 'No final answer found.')

                if intermediate_steps is not None:
                    # Log or process intermediate steps if needed
                    for step in intermediate_steps:
                        logging.debug(f"Intermediate Step: {step}")

                return final_answer

Whenever this function is called, it will return: 'NoneType' object is not iterable.

I expect the output to be the result of the query. Because I want to use function calling with Ollama, only ChatOllama(model=model) can be used (just that you are informed) because ChatOllama is the only class that has .bind_tools() method. All other implementations of Ollama don't implement .bind_tools().

I'm clueless at this point.

Answer 1

messages or messages where role is "user" could be None