def invoke_message(runner: Runner, user_id: str, session_id: str, message_text: str):
    user_message = types.Content(
        role="user",
        parts=[types.Part(text=message_text)]
    )

    for event in runner.run(
        user_id=user_id,
        session_id=session_id,
        new_message=user_message
    ):
        if event.is_final_response():
            if event.content and event.content.parts:
                print(f"Agent: {event.content.parts[0].text}")

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