I put in comments to demonstrate my thinking. What’s the flaw in my thinking?

```
digit_total = 0
def sum_digits(n):
#Defined function, should be good
for i in len(str(n)):
#len(str(n)) should return 4, if n = 1234
digit_total += n % 10
#Should store 4 with sum_digits(1234) before iterating
n // 10
#Gives me a new n removing rightmost digit
#Loops for n-1 more iterations
```

(I get an int is not iterable error.)