Hi! Please, how can I prove this solution? I create a variable x = 1234 but don’t work!! Thanks!!

```
def digit_sum(x):
total = 0
while x > 0:
total += x % 10
x = x // 10
print x
return total
```

Hi! Please, how can I prove this solution? I create a variable x = 1234 but don’t work!! Thanks!!

```
def digit_sum(x):
total = 0
while x > 0:
total += x % 10
x = x // 10
print x
return total
```

That is why there is a simple rule… Don’t use code you didnt’ create if you don’t understand how it works.

Not sure what the problem is on your end. The code looks and works fine. Have you tried calling the function?