init.py

class HauntedBus:
    def __init__(self, passengers=[]):
        self.passengers = passengers
    
    def pick(self, name):
        self.passengers.append(name)
    
    def drop(self, name):
        self.passengers.remove(name)


bus1 = HauntedBus(['Alice', "Bill"])

print(bus1.passengers)

bus1.pick("Charlie")
bus1.drop("Alice")

print(bus1.passengers)

bus2 = HauntedBus()

bus2.pick("Carrie")
print(bus2.passengers)

bus3 = HauntedBus()

print(bus3.passengers)

bus3.pick("Dave")

print(bus2.passengers)

print(bus2.passengers is bus3.passengers)

print(bus1.passengers)

# ['Alice', 'Bill']
# ['Bill', 'Charlie']
# ['Carrie']
# ['Carrie']
# ['Carrie', 'Dave']
# True
# ['Bill', 'Charlie']