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

However the output area gives the accurate output. I manually cross checked the output.

This should be a correct piece of code. I can't quite figure out the mistake. Any help would be appreciated.

```
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)
total=total/len(numbers)
return total
def get_average(student):
homeworkt=average(student["homework"])
quizzest=average(student["quizzes"])
testst=average(student["tests"])
return 0.1*homeworkt+0.3*quizzest+0.6*testst
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=[]
for a in students:
k=get_average(a)
results.append(k)
return average(results)
a=get_class_average([lloyd,alice,tyler])
print a
print get_letter_grade(a)
```