The error am getting:

"Oops, try again. get_class_average([alice]) resulted in an error: 'tuple' object has no attribute 'append'

"

My code is given below:

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

Can somebody illuminate me on why am getting this error.

Thanks,Abhiram.