Getting 83.8666666667 instead of what they are expecting: 91.15

I'm really just not sure what the issue with 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]
}
def average(numbers):
total = sum(numbers)
total = float(total) / len(numbers)
return total
def get_average(student):
return 0.10 * average(student["homework"]) + 0.30 * average(student["quizzes"]) + 0.60 * average(student["tests"])
def get_letter_grade(score):
if score >= 90.0:
return "A"
elif score >= 80 and score < 90:
return "B"
elif score >= 70 and score < 80:
return "C"
elif score >= 60 and score < 70:
return "D"
else:
return "F"
print get_letter_grade(get_average(lloyd))
class_list = [lloyd, alice, tyler]
def get_class_average(students):
results = []
for students in class_list:
results.append(get_average(students))
return average(results)
print get_class_average(classs)
```