Help 9/9 error

#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)
total = 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

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

students = [lloyd, alice, tyler]
print get_class_average(students)

and i get a error
A
83.8666666667
Traceback (most recent call last):
File "python", line 58, in
File "python", line 29, in get_average
TypeError: list indices must be integers, not str

#2