This is my code:

```
def digit_sum(n):
total = 0
str(n)
for number in n:
int(number)
total += number
return total
```

I tried hard to fix it but I couldn’t. This is my error message:

Does your digit_sum function take exactly one argument (a positive integer)? Your code threw a “unsupported operand type(s) for +=: ‘int’ and ‘str’” error.

Can someone please help me?

Thanks