!
        \~english
        Send command to ssd1306, DC pin need set to LOW
        @param commands: an byte or array of bytes

        \~chinese 
        发送命令给 SSD1306，DC 需要设定为低电平 LOW
        @param commands: 一个字节或字节数组

def _command(self, commands):
        """!
        \~english
        Send command to ssd1306, DC pin need set to LOW
        @param commands: an byte or array of bytes

        \~chinese 
        发送命令给 SSD1306，DC 需要设定为低电平 LOW
        @param commands: 一个字节或字节数组
        """
        if self._spi == None: raise "Do not setting SPI"
        GPIO.output( self._spi_dc, 0 )
        self._spi.writebytes( commands )