SPI class is using I2C Device

```python
class LSM9DS1_SPI(LSM9DS1):
    """Driver for the LSM9DS1 connect over SPI."""
    # pylint: disable=no-member
    def __init__(self, spi, xgcs, mcs):
        self._mag_device = spi_device.I2CDevice(spi, mcs)
        self._xg_device = spi_device.I2CDevice(spi, xgcs)
        super().__init__()
```