Fix use of Python 3.9 typing.
Fix use of Python 3.9 typing.

PiperOrigin-RevId: 377406217
Change-Id: I1cc1955312c7ed9c25999c7a6e2551e7e6cfc946

google-research/falken,google-research/falken,google-research/falken,google-research/falken,google-research/falken,google-research/falken,google-research/falken