old_contents: grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
  
  def print_grades(grades):
  	for number in grades:
  		print number
  
  print_grades(grades)
  
  
  def grades_sum(scores):
  	total = 0
  	for item in scores:
  		total += item
  	print total
  
  grades_sum(grades)
  
new_contents: grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
  
  def print_grades(grades):
  	for number in grades:
  		print number
  
  print_grades(grades)
  
  def grades_sum(scores):
  	total = 0
  	for item in scores:
  		total += item
  	print total
  	return total
  
  print grades_sum(grades)
  
  
  def grades_average(grades):
  	return grades_sum(grades) / float(len(grades))
  
  print grades_average(grades)
  
  def grades_variance(scores):
  	average = grades_average(scores)
  	variance = 0
  	for score in scores:
  		variance += (average - score) ** 2
  	variance /= len(scores)
  	return variance
  
  print grades_variance(grades)
  
  
subject: update script for variance of list