Oops, try again. Did you remember to print the letter grade for the class's average?

Traceback (most recent call last):

File "python", line 55, in <module

File "python", line 30, in get_average

TypeError: list indices must be integers, not str

Stuck here...Dont know what happened

I've already add

students = [lloyd,alice,tyler]...

```
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!
# The students's averages!
students = [lloyd,alice,tyler]
def average(numbers):
total = sum(numbers)
total = float(total)
result = total/len(numbers)
return result
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
# The letter grade that student should receive.
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))
# Now let's calculate the class average.
def get_class_average(students):
result = []
for student in students:
result.append(get_average(student))
return average(result)
print get_class_average(students)
print get_letter_grade(get_average(students))
```