trezor-firmware/core/src/trezor/ui/constants/__init__.py

from trezor import utils

if utils.MODEL in ("1",):
    from .t1 import *  # noqa: F401,F403
elif utils.MODEL in ("R",):
    from .tr import *  # noqa: F401,F403
elif utils.MODEL in ("T",):
    from .tt import *  # noqa: F401,F403
else:
    raise ValueError("Unknown Trezor model")