code: def get_firmware_version(self):
          
          cmd_response = self.__send_command(const.CMD_GET_VERSION,b'', 1024)
          if cmd_response.get('status'):
              firmware_version = self.__data.split(b'\x00')[0]
              return firmware_version.decode()
          else:
              raise ZKErrorResponse("Can't read frimware version")
docs: :return: the firmware version