def METHOD_NAME(classmethod_decorator: Any) -> None:
    class Model(BaseModel, revalidate_instances='always'):
        x: int
        y: int
        @model_validator(mode='before')
        @classmethod_decorator
        def val_model(cls, values: Any, info: ValidationInfo) -> dict[str, Any] | Model:
            assert not info.context
            if isinstance(values, dict):
                values = cast(Dict[str, Any], values)
                values['x'] += 1
                values['y'] += 1
            else:
                assert isinstance(values, Model)
                values.x += 1
                values.y += 1
            return values
    assert Model(x=1, y=2).model_dump() == {'x': 2, 'y': 3}
    assert Model.model_validate(Model(x=1, y=2)).model_dump() == {'x': 3, 'y': 4}