python编写检查卡号合理性

编写程序检查用户输入的8位卡号是否合法，具体要求如图：

如何编辑程序？

n = input('请输入8位卡号：')
#请输入8位卡号：43589795
n1 = sum(map(int,list(n[-1::-2])))
n2 = sum(map(int,sum([list(str(i)) for i in map(lambda x:2*int(x),list(n[-2::-2]))],[])))
if (n1 + n2)%10 == 0:
    print('卡号有效！')
    
#卡号有效！

num = input('请输入信用卡号：')

if (sum(int(i) for i in num[::-2]) + sum(int(i) for i in ''.join(str(int(i)*2) for i in num[-2::-2])))%10==0:
    print('有效')
else:
    print('无效')