code: def get_mac(self):
          
          command = const.CMD_OPTIONS_RRQ
          command_string = b'MAC\x00'
          response_size = 1024
  
          cmd_response = self.__send_command(command, command_string, response_size)
          if cmd_response.get('status'):
              mac = self.__data.split(b'=', 1)[-1].split(b'\x00')[0]
              return mac.decode()
          else:
              raise ZKErrorResponse("can't read mac address")
docs: :return: the machine's mac address