You can use simpler types. Instead of :

        messages=[
            GPTMessage(
                role=GPTMessageRole.SYSTEM,
                content=SYSTEM_PROMPT,
            ),
            GPTMessage(
                role=GPTMessageRole.USER,
                content="Text: I love this product. It's the best thing ever!",
            )
        ]

Try:

        messages=(
            ("system", SYSTEM_PROMPT),
            ("user", "Text: I love this product. It's the best thing ever!")
        )

Or:

        messages=(
            SystemMsg(SYSTEM_PROMPT),
            UserMsg("Text: I love this product. It's the best thing ever!")
        )

This is still Python, not Java.