9/9 Review

I am getting a "none" between my print of the grades and my print of the sum of the grades.

Example

50.5

None

Your Total Grade is: 1045.5

I would expect that the none would not be there.

How do I get rid of the "none"

```
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(grades):
average = grades_average(grades)
variance = 0
for grade in grades:
variance +=(average - grade)**2/len(grades)
return variance
print grades_variance(grades)
def grades_std_deviation(variance):
return float(variance) ** 0.5
variance = grades_variance(grades)
print grades_std_deviation(variance)
print 'Your Grades are: \n', print_grades(grades)
print 'Your Total Grade is: ', grades_sum(grades)
print 'Your Average Grade is: ', grades_average(grades)
print 'Your Variance from Average is: ', grades_variance(grades)
print 'Your Standard Deviation is: ', grades_std_deviation(variance)
```