Quiz in Python - Original program ran, but refactored to OOP and does not run now

Simple quiz in Python that reads a csv file in "answer,question" format. The program was running before I decided to try to refactor my original code by attempting to implement OOP. I referenced different sources to determine whether the csv, random, classes and loop were coded correctly, but the code does not run with this updated refactored version.

I do not see what am I doing wrong for it not run with the refactored code. In essence, what am I doing wrong? Am I putting the code in the wrong place for it not run with oop?

import csv
import random 

player_name = input("What is your name? ")
print(f"Welcome, {player_name}, to the Quiz!")
play_quiz = str(input("Are you ready to play? "))
if play_quiz != "y":
    exit()

class Question:
    def __init__(self, prompt, answer):
        self.prompt = prompt
        self.answer = answer

def quiz():
    score = 0
    questions_right = 0
    quiz_file = open(characters_file, "r")
    quiz_data = quiz_file.readlines()
    random.shuffle(quiz_data)
    question_number = 1 
    for question in range(65):
         x = quiz_data[question].strip()
         data = x.split(",")
         Question = data.prompt[1]
         correct_answer = data.answer[1]

def run_test(quiz_data):
    answer = input("What is your answer? ")
    if answer == correct_answer:
         score += 1
         question_right = question_number + 1
    else:
         print("Incorrect.")
         print(f"Correct answer should be: {CorrectAnswer}")

    total_score = (score / 65) * 100 
    print("You answered " + str(score) + "/" + str(total_score) + " question correct.")
    print("You have a score of " + str(total_score) + "%")

    return input("Want to play again? (y/n): ") == "y".lower()

 quiz()
 quiz_file.close()
 play_again = True
 while play_again:
     play_again = run_test()