Python 3.x 在python3中创建十六进制校验和时出现问题

好的，我正在控制一台工业打印机

我需要发送一个十六进制UDP数据包

这是这个包背后的理论

CHKSUM:256模（LEN+ST#+CMD+DATA）之和

我的最后一个包需要看起来像这样 02 00 06 00 46 07 00 005303

def startprint(msgID):
    STX = "02"
    LEN = "0006"
    ST = "00"
    CMD = "46"
    DATA = msgID
    ETX = "03"
     
    CHKSUM = hex(int(LEN,16)+ int(CMD,16) + int(DATA))
    print(CHKSUM[2:])
   
    testmod = int(CHKSUM[2:])%256
    test1 = str(testmod) #This Is Correct
    
    print(test1)          #This is Corret my checksum should be 53
    packet = bytearray();
    packet.append(int(STX))
    packet.append(int(LEN))
    packet.append(int(ST))
    packet.append(int(CMD))
    packet.append(int(DATA))
    packet.append(int(testmod)) #This converts my hex to 5 for some reason, and not 53 
    
    
    print(packet)

startprint("07")

这就是我得到的 字节数组（b'\x02\x06\x00.\x075'）

不知道我哪里出了问题，我的头撞在墙上好几个小时了，四处摸索，毫无进展

我哪里做错了

def startprint(msgID):
    STX = "02"
    LEN = "0006"
    ST = "00"
    CMD = "46"
    DATA = msgID
    ETX = "03"
     
    CHKSUM = hex(int(LEN,16)+ int(CMD,16) + int(DATA))
    print(CHKSUM[2:])
   
    testmod = int(CHKSUM[2:])%256
    test1 = str(testmod) #This Is Correct
    
    print(test1)          #This is Corret my checksum should be 53
    packet = bytearray();
    packet.append(int(STX))
    packet.append(int(LEN))
    packet.append(int(ST))
    packet.append(int(CMD))
    packet.append(int(DATA))
    packet.append(int(testmod)) #This converts my hex to 5 for some reason, and not 53 
    
    
    print(packet)

startprint("07")