it keeps erroring

https://www.codecademy.com/courses/python-intermediate-en-7mgOa/2/1?curriculum_id=4f89dab3d788890003000096

Oops, try again. You did not print the correct variance. Double-check your code and make sure you print the variance!

```
Replace this line with your code.
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
def print_grades(grades):
for grade in grades:
return 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(scores)
variance=0
for score in scores:
variance +=(average-score)**2
variance=variance/len(scores)
return variance
print variance
```