Importing two text files to compare as lists sequentially - python-3.7

Question

Student trying to compare two .txt files of string "answers" from a multiple choice test a,c,d,b, etc. I've found some information on different parts of the problems I'm having and found a possible way to get the comparisons I want, but the guide was meant for in script strings and not pulling a list from a file.
For the import of the two files and comparing them, I'm basing my code on my textbook and this video here: Video example
I've got the code up and running, but for some reason I'm only getting 0.0% match when I want to a 100.0% match, at least for the two text files I'm using with identical answer lists.
import difflib
answer_sheet = "TestAnswerList.txt"
student_sheet = "StudentAnswerList.txt"
ans_list = open(answer_sheet).readlines()
stu_list = open(student_sheet).readlines()
sequence = difflib.SequenceMatcher(isjunk=None, a=ans_list, b=stu_list)
check_list = sequence.ratio()*100
check_list = round(check_list,1)
print(str(check_list) + "% match")
if check_list == 100:
print('This grade is Plus Ultra!')
elif check_list >= 75:
print('Good job, you pass!')
else:
print('Please study harder for your next test.')
# not the crux of my issue, but will accept advice all the same
answer_sheet.close
student_sheet.close
If I add in the close statement at the end for both of the text files, then I receive this error:
Traceback (most recent call last): File
"c:/Users/jaret/Documents/Ashford U/CPT 200/Python Code/Wk 5 Int Assg
- Tester code.py", line 18, in
answer_sheet.close AttributeError: 'str' object has no attribute 'close'

Answer 1

I had to re-look at how my files were being opened and realized that the syntax was for Python 2 not 3. I chose to go w/ basic open and later close to reduce any potential errors on my novice part.
import difflib
f1 = open('TestAnswerList.txt')
tst_ans = f1.readlines()
f2 = open('StudentAnswerList.txt')
stu_ans = f2.readlines()
sequence = difflib.SequenceMatcher(isjunk=None, a=stu_ans, b=tst_ans)
check_list = sequence.ratio()*100
check_list = round(check_list,1)
print(str(check_list) + "% match") # Percentage correct
if check_list == 100:
print('This grade is Plus Ultra!')
elif check_list >= 75:
print('Good job, you pass!')
else:
print('Please study harder for your next test.')
# Visual Answer match-up
print('Test Answers: ', tst_ans)
print('Student Answers:', stu_ans)
f1.close()
f2.close()