Hi. I’m with no best alternatives. I don’t know what it’s necessary to correct the code below:

```
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
def grades_sum(scores):
total = 0.0
for i in range(len(scores)):
total = sum(float(i) for i in scores)
print total
grades_sum(grades)
```

I would like to know why I’m receiving the *error alert*, “It returned None”, when if i to put some values, in list format, like `grades_sum([45, 32])`

the function returns the correct sum: 77.0

Error alert:

Oops, try again. It looks like your grades_sum function doesn’t properly compute the sum of all the grades!It returned Noneinstead of 324 for grades_sum([73, 50, 44, 68, 89])