Part of the whole

Oops, try again. get_class_average([alice]) should return a number

I don't know what's wrong in this code. Help me to find out.

```
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]
}
# Add your function below!
def average(numbers) :
total=sum(numbers)
total=float(total)/ len(numbers)
return total
def get_average(student) :
homework=average(student["homework"])
quizzes=average(student["quizzes"])
tests=average(student["tests"])
homework=homework * 0.1
quizzes=quizzes * 0.3
tests=tests * 0.6
return homework+quizzes+tests
def get_letter_grade(score) :
if score>=90:
return "A"
elif score>=80:
return "B"
elif score>=70:
return "C"
elif score>=60:
return "D"
else:
return "F"
print get_letter_grade
print get_letter_grade(get_average(lloyd))
def get_class_average(students):
students = [lloyd, alice, tyler]
results=[]
for student in students:
results.append(get_average(student))
return results
```