class Observable(object):def __init__(self):self.observers = []def add_observer(self, observer):if not observer in self.observers:self.observers.append(observer)def remove_observe(self, observer):if observer in self.observers:self.observers.remove(observer)def remove_all_observers(self):self.observers = []　　 #更新Observerdef update_observable(self):for observer in self.observers:observer.update_observer()

class Game(Observer):#注：只截取了与观察者模式有关的代码部分def update_observer(self):self.__total_monsters = self.__total_monsters - 1if self.__total_monsters <= 0:  # Winning conditionprint('You Win!\nYour neighborhood is now safe.')

class House(Observer, Observable):　　 #注：只截取了与观察者模式有关的代码部分 def update_observer(self):# Remove any monsters with health <= 0.for m in self.__monsters:if m.get_hp() <= 0:self.__monsters.remove(m)self.__house_monsters = self.__house_monsters - 1# Now add a person to replace the monster.person = Person()self.__monsters.append(person)# Update the game object observing.self.update_observable()

class House(Observer, Observable):def update_observer(self):# Remove any monsters with health <= 0.for m in self.__monsters:if m.get_hp() <= 0:self.__monsters.remove(m)self.__house_monsters = self.__house_monsters - 1# Now add a person to replace the monster.person = Person()self.__monsters.append(person)# Update the game object observing.self.update_observable()

class Monster(Npc, Observable):def monster_defence(self, weapon, attack):# Calculate the damage from player's weapon.damage = self.get_multiplier(weapon) * attack * \weapon.get_mult()health = self.get_hp() - damageself.set_hp(health)if health <= 0:print('%s defeated! It became a helpful human!'% (Monster.monster_id[self.get_id()]))Monster.__decrement_monster_count()　　　　　　  #更新观察者house    # Update all houses watching of a monster purified.self.update_observable()else:print("%s hit for %.1f damage, now at %.1f health points."% (Monster.monster_id[self.get_id()], damage, health))