It is overall correct and same as the model code. However I do not understand under the function get_letter_grade(score):, since score has never been defined. It is neither a global nor local variable so why does it work?

Any answers would be helpful, thanks!

```
Replace this line with your code.
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(sum(numbers)) / float(len(numbers))
return total
def get_average(student):
homework = average(student["homework"])* 0.1
quizzes = average(student["quizzes"])* 0.3
tests = average(student["tests"])* 0.6
avrg = homework + quizzes + tests
return avrg
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(lloyd)
students = [lloyd, alice, tyler]
def get_class_average(students):
results = []
for student in students:
get_average(student)
total = get_average(student)
results.append(total)
return average(results)
print get_class_average(students)
print get_letter_grade(students)
print get_letter_grade(get_class_average(students))
```