将其写入文件的正确语法是什么?

def guessingTime(answer, username):
    vdfile = open("victorydefeat.txt", "a")
    now = time.asctime(time.localtime(time.time()))
    victory = username + "successfully guess" + answer + "on" + now
    defeat = username + "was unable to guess" + answer + "on" + now
    print("That's 20! Time to guess.")
    guess = input("Is it a(n): ")
    if guess.lower() == answer:
        print("You got it! Congratulations!")
        vdfile.write(victory)
        vdfile.write("\n")
    else:
        print("Sorry, but the answer was", answer)
        vdfile.write(now)
        vdfile.write("\n")
    vdfile.close()

def main():
    print("Welcome to 20 questions! The game where I (your humble program) will think of an object and you (the beloved user) will try to guess it!")
    username = print(input(("Now, before we begin, I'd like to know your name (for recording purposes): ")))
    infile1, infile2, answer = getAnswer()
    #startAsking(infile1, infile2)
    guessingTime(answer, username)

main()

对于“胜利=”行,错误消息为“不支持+='NoneType'和'str'的操作数类型”。我想写:“成功猜中了”。我该怎么做?