comparing two lists

[Siylo]

Okay, so I was playing around and I have an error I don't know how to fix.

def main():

    # Constant of correct test answers.
    CORRECT_ANSWERS = ["A" , "C" , "A" , "A" , "D" ,
                       "B" , "C" , "A" , "C" , "B" ,
                       "A" , "D" , "C" , "A" , "D" ,
                       "C" , "B" , "B" , "D" , "A"]

    # filling a list with every line, stripped of the \n, from the opened file
    student_answers = [line.strip('\n') for line in open('test.txt', 'r')]

    student_correct = 0
    incorrect_num = [(index + 1) if CORRECT_ANSWERS[index] != student_answers[index] else
                     (student_correct +1) for index in CORRECT_ANSWERS]

    print(incorrect_num)


main()

The error is

Error:
Traceback (most recent call last):File "", line 15, in <listcomp>
    (student_answers +1) for index in CORRECT_ANSWERS]
TypeError: list indices must be integers or slices, not str

I fixed the student_answers +1 to student_correct +1. I noticed it after but it doesn't change the error.