i need help on the lesson and have no idea what i am doing wrong

https://www.codecademy.com/courses/python-beginner-en-qzsCL/1/4?curriculum_id=4f89dab3d788890003000096

Oops, try again. get_class_average([alice]) resulted in an error: 'float' object has no attribute 'append'

```
Replace this line with your code.
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)
return total / len(numbers)
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
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"
def get_class_average(students):
results: []
results = get_average(student)
results.append(results)
return average(results)
```