```
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 = 0
for score in scores:
average += grades_average(scores)
variance = 0
for score in scores:
variance += (average - score)**2
return variance/len(scores)
print (grades_variance(grades))
```

Oops, try again. grades_variance([9, 0, 4, 2, 5, 9, 2, 3]) returned 894.5 instead of the expected: 9.4375

I get this message as a result. What's wrong with mine?