code: def _command(self, commands):
          
          if self._spi == None: raise "Do not setting SPI"
          GPIO.output( self._spi_dc, 0 )
          self._spi.writebytes( commands )
docs: !
          \~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