https://www.codecademy.com/courses/python-intermediate-en-rCQKw/0/4?curriculum_id=4f89dab3d788890003000096

I had hoped to return a neat solution to the digit_sum problem without going into too much unfamiliar coding which I would soon forget. I must be over-simplifying the problem and my solution is None.

I expect it will take some further understanding of global/local variables.

```
def digit_sum(n):
total = 0
[int(i) for i in str(n)]
while i < len(str(n)):
total += n[i]
```