hi,

the instrucions are:

Write a function called digit_sum that takes a positive integer n as input and returns the sum of all that number's digits.

For example: digit_sum(1234) should return 10 which is 1 + 2 + 3 + 4.

(Assume that the number you are given will always be positive.)

this is my code:

```
def digit_sum(n):
y = str(n)
summa = 0
for ch in y:
f = summa + int(ch)
summa.append(f)
return summa
```

thank you for your help