while n>0:
        d=n%10
        n=n//10
        sum+=d

def sumdigits(n):
    sumd = 0
    while n > 0:
        n,d = divmod(n, 10)
        sumd += d
    return sumd

items = [123, 567, 899, 999]

res = max(items, key=sumdigits)

print(res)
#999

def sumdigits(n):
    return sum([ int(i) for i in str(n) ])

items = [123, 567, 899, 999]
res = max(items, key=sumdigits)
print(res)
999