初学者求教，关于python,类定义完成没有实例就自己运行了？

from sys import exit
from random import randint
from textwrap import dedent

print("从这里开始的？")
class Engine(object):  
    # 非得带object? Engine 意思是引擎 游戏的引擎
    def __init__(self, fangjianming):
        self.name = fangjianming

    def play(self):
        dqcj = self.name.dakai()
        zzcj = self.name.xiayige('zuihou')
        while dqcj != zzcj:
            print("到这里了吗")
            xiagechangjing = dqcj.enter()  # dqcj就是获得的类名字 用xingechangjing 来实例化
            dqcj = self.name.xiayige(xiagechangjing)
        dqcj.enter()

print("从这里开始的？1")
class Fj1():
    print("""这是第一个房间
            这个房间你可以寻找到武器，
            试着输入 xunzhao  tuichu
            """)

    def enter(self):

        choice = input("输入提示让你输入的>>>>>  ")
        if choice == "xunzhao":
            print("你找到了一把枪")
            return 'fj1'
        elif choice == "tuichu":
            print("你回到了走廊")
            return 'zoulang'
        else:
            print("你说的什么啊？")
            return 'fj1'

print("从这里开始的？2")
class Fj2():
    print("""这是第二个房间
            这个房间你可以寻找到炸弹，
            试着输入 xunzhao  tuichu
            """)

    def enter(self):
        choice = input("输入提示让你输入的>>>>>  ")
        if choice == "xunzhao":
            print("你找到了一个炸弹")
            return 'fj2'
            # 这里完善的时候可以加一个判断，如果已经找到炸弹  炸弹类里面的属性变为真，则输出不能再找到炸弹
        elif choice == "tuichu":
            print("你回到了走廊")
            return 'zoulang'
        else:
            print("你说的什么啊？")
            return 'fj2'

print("从这里开始的？3")
class Zoulang():
    print("""这是一个走廊.
            从这里你可以进入飞船上的房间，
            试着输入 fj1 fj2 zoulang end
            """)

    def enter(self):
        choice = input("输入提示让你输入的>>>>>  ")
        if choice == "fj1":
            print("你走到了房间1的门前，准备进入")
            return 'fj1'
            # 这里完善的时候可以加一个判断，如果已经找到炸弹  炸弹类里面的属性变为真，则输出不能再找到炸弹
        elif choice == "fj2":
            print("你走到了房间2的门前，准备进入")
            return 'fj2'
        elif choice == "zuihou":
            print("你不想玩了")
            return 'zuihou'
        else:
            print("你说的什么啊？")
            return 'zoulang'

print("从这里开始的？4")
class zuizhong():
    print("你完成了整个游戏")
    #exit(1)

print("从这里开始的？5")
class Map(object):
    mapname = {
        'fj1': Fj1(),
        'fj2': Fj2(),
        'zoulang': Zoulang(),
        'zuihou': zuizhong(),
    }
    print("这里你总要运转到吧")
    def __init__(self, start_name):
        self.start_name = start_name

    def xiayige(self, fangjianming):
        val = Map.mapname.get(fangjianming)
        return val
        print("1",val)
    def dakai(self):
        return self.xiayige(self.start_name)
        print("2",self.xiayige(self.start_name))

#a_test = Map('fj2')
print("zheli?")
#a_game = Engine(a_test)
print("haishizheli?")
#a_game.play
print("zuihouzheli?")