# ModelBase is not considered either "frozen" or "non-frozen"
# because it is decorated with ``dataclass_transform``
@typing.dataclass_transform()
class ModelBase(): ...

# Vehicle is considered non-frozen because it does not specify
# "frozen=True".
class Vehicle(ModelBase):
    name: str

# Car is a frozen class that derives from Vehicle, which is a
# non-frozen class. This is an error.
class Car(Vehicle, frozen=True):
    wheel_count: int