Hi! Can anybody tell where I did wrong in the last part: calculate the whole average?

# Add your function below!

students={lloyd,alice,tyler}

def average(numbers):

total=sum(numbers)

total=float(sum(numbers))

result=total/len(numbers)

return result

print result

def get_average(student):

return 0.1*average(student["homework"]) + \

0.3*average(student["quizzes"]) + \

0.6*average(student["tests"])

def get_letter_grade(score):

if score>=90.0:

return "A"

elif score>=80.0:

return "B"

elif score>=70.0:

return "C"

elif score>=60.0:

return "D"

else:

return "F"

print get_letter_grade(average(lloyd))

def get_class_average(students):

results=[]

for students in students:

results.append(get_average(student))

return results