m3vict[m]: ```
impl<Spi> MyDevice<Spi, u8>
where
    Spi: SpiDevice<u8>,
{
    fn write_command(&mut self, cmd: Command, data: u16) -> Result<(), Error> {
        // do u8 SPI transfer
    }
}
```
and
```
impl<Spi> MyDevice<Spi, u16>
where
    Spi: SpiDevice<u16>,
{
    fn write_command(&mut self, cmd: Command, data: u16) -> Result<(), Error> {
        // do u16 SPI transfer
    }
}
```