```
def digit_sum(n):
digits=[]
for d in str(n):
digits.append(int(d))
b=sum(digits)
return b
```

Oops, try again. Your function fails on digit_sum(434). It returns 4 when it should return 11.

```
Replace this line with your code.
Can somebody help me to check or correct it? I have struggled few days for this one.
```