code: def command(self, c):
          
          if self._spi is not None:
              # SPI write.
              self._gpio.set_low(self._dc)
              self._spi.write([c])
          else:
              # I2C write.
              control = 0x00   # Co = 0, DC = 0
              self._i2c.write8(control, c)
docs: Send command byte to display.