# 8.Partof the Whole - Not sure what is wrong with my code !?

#1

lloyd = {
"name": "Lloyd",
"homework": [90.0, 97.0, 75.0, 92.0],
"quizzes": [88.0, 40.0, 94.0],
"tests": [75.0, 90.0]
}
alice = {
"name": "Alice",
"homework": [100.0, 92.0, 98.0, 100.0],
"quizzes": [82.0, 83.0, 91.0],
"tests": [89.0, 97.0]
}
tyler = {
"name": "Tyler",
"homework": [0.0, 87.0, 75.0, 22.0],
"quizzes": [0.0, 75.0, 78.0],
"tests": [100.0, 100.0]
}

def average(numbers):
total=sum(numbers)
total=float(total)
average=total/len(numbers)
return average

def get_average(student):
homework=average(student["homework"])
quizzes=average(student["quizzes"])
tests=average(student["tests"])
return 0.1*homework + 0.3*quizzes + 0.6*tests

if score >= 90:
return "A"
elif score >= 80:
return "B"
elif score >= 70:
return "C"
elif score >= 60:
return "D"
else:
return "F"

students = [lloyd, alice, tyler]

def get_class_average(students):
results=[]
for student in students:
results=results.append(get_average(student))
print results
return average(results)

Error:Oops, try again. get_class_average([alice]) resulted in an error: 'NoneType' object is not iterable

#2

The problem is when you call the append function :

for student in students:
results=results.append(get_average(student))
print results

By doing this results which was a list becomes a NoneType object.
The right way to call the append method is to write :

for student in students:
results.append(get_average(student))
print results