Ex43.py - 'NoneType' object has no attribute 'enter'

Hi guys,

At my wits end with this one. I’ve found answers elsewhere online, but none that have fixed my issuse. I’m getting ‘NoneType’ object has no attribute ‘enter’ in certain instances when I run the game.

All the rooms have returns, but it’s still not running. Could anyone help?


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

class Scene(object):

def enter(self):
    print("This scene is not yet configured.")
    print("Subclass it and implement enter.()")

class Engine(object):

def __init__(self, scene_map):
    self.scene_map = scene_map

def play(self):
    current_scene = self.scene_map.opening_scene()
    last_scene = self.scene_map.next_scene('finished')

    while current_scene != last_scene:
            next_scene_name = current_scene.enter()
            current_scene = self.scene_map.next_scene(next_scene_name)


class Death(Scene):

quips = [
    "You died. You kinda suck at this.",
    "Your Mum would be proud...if she were smarter.",
    "Such a luser.",
    "I have a small puppy that's better at this.",
    "You're worse than your dads jokes",


def enter(self):
    print(Death.quips[randint(0, len(self.quips)-1)])
    return "finished"

class CentralCorridor(Scene):

def enter(self):
        The Gothons of Planet Percal #25 have invaded your ship and destroyed
        your entire crew.  You are the last surviving member and your last
        mission is to get the neutron destruct bomb from the Weapons Armory,
        put it in the bridge, and blow the ship up after getting into an
        escape pod.

        You're running down the central corridor to the Weapons Armory when
        a Gothon jumps out, red scaly skin, dark grimy teeth, and evil clown costume
        flowing around his hate filled body.  He's blocking the door to the
        Armory and about to pull a weapon to blast you.

    action = input("> ")

    if action == "shoot!":
            Quick on the draw you yank out your blaster and fire it at the Gothon.
            His clown costume is flowing and moving around his body, which throws
            Off your aim. Your laser hits his costume but misses him entirely. This
            completely ruins his brand new costume his mother bought him,which
            makes him fly into an inscane rage and blast you repeatedly in the face until
            you are dead. Then he eats you.
        return "Death"

    elif action == "dodge!":
            Like a world class boxer you dodge, weave,slip and slide right
            as the Gothon's blaster cranks a laser past your head.
            In the middle of your artful dodge your foot slips and you
            bang your head on the metal wall and pass out.
            You wake up shortly after only to die as the Gothon stomps on
            your head and eats you.
        return "Death"

    elif action == "tell a joke":
            "Lucky for you they made you learn Gothon insults in the academy.
            You tell the one Gothon joke you know:
            Lbhe zbgure vf fb sng, jura fur fvgf nebhaq gurubhfr,fur fvgf nebhaq gur ubhfr.
            he Gothon stops,tries not to laugh, then busts out laughing and can't move.
            While he's laughing ou run up and shoot him square in the head
            putting him down, then jump through the weapon Armory door.
        return 'laser_weapon_armory'

        print("DOES NOT COMPUTE")
        return "central_corridor"

class LaserWeaponArmory(Scene):

def enter(self):
        You do a dive roll into the weapon armory,crouch and scan the room
        for more gothons that might be hiding. It's dead quiet,too quiet.
        You stand up and run to the far side of the room and find the
        neutron bomb in its container. There's a keypad lock on the box
        and you need the code to get the bomb out. If you get the code
        wrong 10 times then the lock closes forever and you can't
        get the bomb. the code is 3 digits.

    code = f"333"
    guess = input("[keypad]>")
    guesses = 0

    while guess != code and guesses < 10:
        guesses += 1
        guess = input("[keypad]> ")

    if guess == code:
            The container clicks open and the seal breaks,letting gas out.
            you grab the neutron bomb and run as fast as you can to the
            bridgs where you must place it in the right spot.
        return "the_bridge"
            The lock buzzes on last time and then you heara sickening
            melting sound as the mechanism is fused together.
            you decide to sit there, and finall the gothons blow up the
            ship from their ship and you die.
        return "Death"

class TheBridge(Scene):

def enter(self):
        You burst ont othe bridge wiht hte neutron destruct bomb
        under your arm and surprise 5 gothons who are trying to
        take control of the ship. Each of them has an even uglier
        weapons out yet, as they see the active bomb under your
        arm and don't want to set it off.

    action = input("> ")

    if action == "throw the bomb":
            In a panic you throw the bomb at the group of gothons
            and make a leap for the door. right as you drop it a
            gothon shoots you right in the back killing you.
            as you die you see another gothon frantically try to disarm
            the bomb. you die knowing they will probably blow up when
            it goes off.
        return "Death"

    elif action == "slowly place the bomb":
            You point your blaster at the bomb under your arm
            and the gothons put their hands up and start to sweat.
            you inch backward to the door, open it, and then carefully
            place the bomb on the floor,pointing your blaster at it.
            you then jump back through the door,punch the close button
            and blast the lock so the gothons can't get out.
            Now that the bomb is placed you run to the escape pod to
            get off this tin can.
        return "EscapePod"

        print("DOES NOT COMPUTE!")
        return "the_bridge"

class EscapePod(Scene):

def enter(self):
        You rush through the ship desperately trying to make it to
        the escape pod before the whole ship explodes. it seems like
        hardly any gothons are on the ship, so your run is clear of
        interference. you get to the chamber with the escape pods ,and
        now need to pick one to take. some of them could be damaged
        but you don't have time to look. there's 5 pods, which one
        print "do you take?

    good_pod = randint(1,5)
    guess = input("[pod #]> ")

    if int(guess) != good_pod:
            you jump into pod {guess} and hit the eject button. {guess}
            the pod escapes out into the void of space, then
            implodes as the hull ruptures, crushing your body
            into jam jelly.
        return "Death"

            You jump into pod {guess} and hit the eject button. {guess}
            rint the pod easily slides out into space heading to
            the planet below. as it flies to the planet,you look
            back and see your ship implode then explode like a
            bright star,taking out the gothon ship at the same
            time. you won!
        return "finished"

class Finished(Scene):

def enter(self):
    print("You won! Good job.")
    return "finished"

class EmptyScene(Scene):

def enter(self):
    return 'finished'

class Map(object):

scenes= {
"central_corridor": CentralCorridor(),
"laser_weapon_armory": LaserWeaponArmory(),
"the_bridge": TheBridge(),
"escape_pod": EscapePod(),
"death": Death(),
"finished": Finished(),

def __init__(self, start_scene):
    self.start_scene = start_scene

def next_scene(self, scene_name):
    val = Map.scenes.get(scene_name)
    return val

def opening_scene(self):
    return self.next_scene(self.start_scene)

a_map = Map(“central_corridor”)
a_game = Engine(a_map)

Ex 43 AttributeError: 'NoneType' object has no attribute 'enter'


I haven’t really studied your code but I can see that some of your scenes return keys that don’t match the keys in Map.scenes, e.g. 'Death' instead of 'death'. If you query a non-existent key with dict.get, it returns None. And then the whole thing blows up because you try to call enter on something that you believe is a Room, but is actually None.

Does this make sense?

Hi Florian!

It does - I’ve gone through to ensure that they all contain the exact same text (caps etc) but still recieve the same error

All sorted now. I trawled through the code and that I was trying to return the escape pod class without the underscore!