This is my code

```
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
def print_grades(grades):
for grade in grades:
print grade
def grades_sum(grades):
total = 0
for grade in grades:
total += grade
return total
def grades_average(grades):
sum_of_grades = grades_sum(grades)
average = sum_of_grades / float(len(grades))
return average
def grades_variance(scores):
average=grades_average(grades)
variance=0
for i in scores:
variance=variance+(average - i)**2
variance=float(variance)/len(scores)
return variance
grades_variance(grades)
print grades_variance(grades)
```

The error is:

Oops, try again. grades_variance([0, 5, 3, 0, 6, 8]) returned 5900.4354043392 instead of the expected: 8.8888888889

Can someone guide me? I am not understanding the error.