The error that i am getting is "get_class_average([alice]) resulted in an error: ‘float’ object is not iterable"

exercise url: https://www.codecademy.com/courses/learn-python/lessons/student-becomes-the-teacher/exercises/part-of-the-whole?action=lesson_resume

My code is :

```
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)
return float(total)/len(numbers)
def get_average(lloyd):
homework = average (lloyd["homework"])
quizzes = average(lloyd["quizzes"])
tests = average(lloyd["tests"])
return 0.1 * homework + 0.3 * quizzes + 0.6 * 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(get_average(lloyd))
def get_class_average(class_list):
results = []
for student in class_list:
student_average = get_average(student)
results.append(student_average)
return average(student_average)
```