It says

Oops, try again.

It looks like your grades_sum function doesn't properly compute the

sum of all the grades! It returned 78 instead of 320 for grades_sum([34,

9, 28, 62, 74, 11, 5, 97])

```
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
def grades_sum(a_list_of_grades):
total = 0
for i in range(int(len(grades))):
total = total + i
return total
```