def setup_device(self, device: torch.device) -> None:
        """
        Raises:
            ValueError:
                If the selected device is not CPU.
        """
        if device.type != "cpu":
            raise ValueError(f"Device should be CPU, got {device} instead.")

        Raises:
            ValueError:
                If the selected device is not CPU.
        
src/lightning/fabric/accelerators/cpu.py