"""
>>> bus1 = HountedBus(['Alice', 'Bill'])
>>> bus1.passengers
['Alice', 'Bill']
>>> bus1.pick('Charlie')
>>> bus1.drop('Alice')
>>> bus1.passengers
['Bill', 'Charlie']
>>> bus2 = HountedBus()
>>> bus2.pick('Carrie')
>>> bus2.passengers
['Carrie']
>>> bus3 = HountedBus()
>>> bus3.passengers
['Carrie']
>>> bus3.pick('Dave')
>>> bus2.passengers
['Carrie', 'Dave']
>>> bus2.passengers is bus3.passengers
True
>>> bus1.passengers
['Bill', 'Charlie']


>>> dir(HountedBus.__init__)  # doctest: +ELLIPSIS
['__annotations__', '__call__', ..., '__defaults__', ...]
>>> HountedBus.__init__.__defaults__
(['Carrie', 'Dave'],)
>>> HountedBus.__init__.__defaults__[0] is bus2.passengers
True

"""

# BEGIN HAUNTED_BUS_CLASS
class HountedBus:
    """A bus model hounted by ghost passengers"""

    def __init__(self, passengers=[]):  # <1>
        self.passengers = passengers  # <2>

    def pick(self, name):
        self.passengers.append(name)  # <3>

    def drop(self, name):
        self.passengers.remove(name)
# END HAUNTED_BUS_CLASS