code: def send_sysex(self, sysex_cmd, data):
          
          msg = bytearray([START_SYSEX, sysex_cmd])
          msg.extend(data)
          msg.append(END_SYSEX)
          self.sp.write(msg)
docs: Sends a SysEx msg.
  
          :arg sysex_cmd: A sysex command byte
          : arg data: a bytearray of 7-bit bytes of arbitrary data