Maths Quiz with Plot

from random import randint
import matplotlib.pyplot as plot

def getPlayerName():
    #get the players name
    name = input('Enter your name: ').strip()
    if name == '':
        name = 'Unknown'
    return name

def loadHighscores():
    #load highscores and add to scores and names lists
    scores = []
    names = []
    try:
        with open('highscore.txt','r') as f:
            for line in f:
                line = line.strip('\n')
                line = line.split(' ')
                names.append(line[0])
                scores.append(line[1])
    except FileNotFoundError:
        print('Creating New Highscore File')
        f = open('highscore.txt','w')
        f.write('Unknown 0')
        f.close()
    return names,scores


def displayHighScores(names,scores):
    #print highscore table
    print('')
    print('NAME','\t','SCORE')
    for pos in range(len(names)):
        print(names[pos],'\t',scores[pos])
    print('')


def updateHighscores(names,name,scores,score):
    #find the correct position for current score and insert into names scores lists
    pos = 0
    for current in scores:
        if score < int(current):
            pos += 1
    scores.insert(pos,score)
    names.insert(pos,name)
    scores = scores[:10]
    names = names[:10]
    return names,scores

def saveHighscores(names,scores):
    #write names and scores lists to highscore textfile
    try:
        with open('highscore.txt','w') as f:
            for pos in range(len(scores)):
                f.write(names[pos] + ' ' + str(scores[pos]) + '\n')
    except FileNotFoundError:
        print('Creating New Highscore File')
        f = open('highscore.txt','w')
        f.write('Unknown 0')
        f.close()


def askQuestion(question):
    #ask math question
    a = randint(1,5)
    b = randint(1,7)
    c = randint(1,9)
    answer = a * b * c
    notValid = True
    while notValid:
        try:
            response = int(input('{}. What is the product of {} * {} * {} ? '.format(question,a,b,c)))
            notValid = False
        except:
            print('Invalid Input')
            notValid = True
    return answer,response


def playAgain():
    again = input('Do you want to play again (Y/N) ?').upper()
    if again == 'Y':
        return True
    else:
        return False

def welcome():
    print('Welcome to the maths quiz')
    print('Answer as many questions as you can')

def goodbye():
    print('Goodbye, thank you for playing')

def quiz():
    #ask questions until player gets one wrong
    name = getPlayerName()
    score = 0
    ask = True
    question = 0
    while ask:
        question += 1
        answer, response = askQuestion(question)
        if answer == response:
            score += 1
            #print('Correct, Score is {}'.format(score))
        else:
            print('Incorrect. The correct answer is {}'.format(answer))
            print('{}, you scored {}'.format(name,score))
            ask = False
    return name,score

def game(names,scores):
    again = True
    while again:
        name,score = quiz()
        names,scores = updateHighscores(names,name,scores,score)
        saveHighscores(names,scores)
        again = playAgain()
    return names,scores

def showPlot(names,scores):
    plot.bar(names,scores)
    plot.title('Math Quiz Scores')
    plot.ylabel('Scores')
    plot.xlabel('Names')
    #plot.gca().invert_yaxis()
    #plot.gca().invert_xaxis()
    plot.show()

#function calls
welcome()
names,scores = loadHighscores()
displayHighScores(names,scores)
names,scores = game(names,scores)
displayHighScores(names,scores)
showPlot(names,scores)
goodbye()