after adding

```
print get_class_average(students)
print get_letter_grade(students)
```

i get the Error:

Traceback (most recent call last):

File "python", line 50, in

File "python", line 46, in get_class_average

File "python", line 27, in get_average

TypeError: list indices must be integers, not str

and

Oops, try again. One of the following is missing or broken when we tried to use it: alice, lloyd, tyler, students, get_class_average, get_letter_grade

didn´t expect an error in previous lines

```
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]
}
students = [lloyd, alice, tyler]
# Add your function below!
def average(numbers):
total = float(sum(numbers)) / len(numbers)
return total
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.append(get_average(students))
return average(results)
print get_class_average(students)
print get_letter_grade(students)
```