Why we need log the start_time and end_time in ask method?

        for answer in self.answers:
            if answer == True:

import datetime
import random

from questions import Add, Multiply


class Quiz:
    questions = []
    answers = []

    def __init__(self):
        question_types = (Add, Multiply)
        # generate 10 random questions with numbers from 1 to 10
        for _ in range(10):
            num1 = random.randint(1, 10)
            num2 = random.randint(1, 10)
            question = random.choice(question_types)(num1, num2)
            # add these questions into self.questions
            self.questions.append(question)

    def take_quiz(self):
        # log the start time
        self.start_time = datetime.datetime.now()

        # ask all of the questions
        for question in self.questions:
            # log if they got the question right
            self.answers.append(self.ask(question))
        else:
            # log the end time
            self.end_time = datetime.datetime.now()

        # show a summary
        return self.summary()


    def ask(self, question):
        correct = False
        # log the start time
        #question_start = datetime.datetime.now()

        # capture the answer
        answer = input(question.text + ' = ')

        # check the answer
        if answer == str(question.answer):
            correct = True

        # log the end time
        #question_end = datetime.datetime.now()

        # if the answer's right, send back True
        # otherwise, send back False
        # send back the elapsed time, too
        return correct #, question_end - question_start

    def total_correct(self):
        # return the total # of correct answers
        total = 0
        for answer in self.answers:
            if answer == True:
                total += 1
        return total

    def summary(self):
        # print how many you got right and the total # of questions. 5/10
        print("You got {} out of {} right.".format(
                self.total_correct(), len(self.questions)
        ))
        # print the total time for the quiz: 30 seconds!
        print("It took you {} seconds total.".format(
                (self.end_time-self.start_time).seconds
        ))


Quiz().take_quiz()