为什么此检查用户输入内容的代码无法正常工作？

当我问用户他们想要使用哪个对象的程序时，会忽略elif语句。

from __future__ import print_function
import random

#Variables

name = raw_input
answer = raw_input
objectList = ['coin', 'piece of paper', 'bundle of sticks']

#Game code

def game():
    name = raw_input("What is your name?: ")
    print ('-----------------------------------------------------------------')
    print ('Hello, ' +  str(name) + ', you tripped into a hole and fell unconcious')
    print ('to wake up in a dungeon. There is a door in front of you, but it ')
    print ('seems to be locked.')
    print ("\n")
    print ('Look around for a tool?')
    askForObject()


#answer for question
def askForObject():
    if "yes" in answer():
        print('-----------------------------------------------------------------')
        print('There are two objects on the ground; a mysterious contraption with')
        print('two prongs, and a ' + random.choice(objectList) + '.')
        print("\n")
        print('Which tool will you pick up? The contraption or the object?')
        pickUpPrompt()               
    else:
        print('What do you mean? Yes, or no?')
        askForObject()

        #ask the user what tool they will pick up
def pickUpPrompt():
    if 'object' in answer():
        print('You picked up the object, but it has no apparent use on the door')
        print('Try again')
        pickUpPrompt()
    elif 'contraption' in answer():
            print('You picked up the contraption.')
            doorPrompt()    
    else:
        print('What object are you talking about?')
        pickUpPrompt()
def doorPrompt():
    print ('-----------------------------------------------------------------')
    print ('Will you use the contraption on the door?')
    if 'yes' in answer():
        print ('door')

game()

我尝试使用其他运算符代替，但是在调用字符串的方式时遇到了问题。如果您两次输入相同的答案似乎很有效，但我不知道为什么。