parent and child

class Parent(object):

    def __init__(self, username, password):
        self.username = username
        self.password = password

    def _get_name(self):
        return self.username.upper()

    def child_action(self):
        return Child(self.username, self.password)


class Child(Parent):

    def __init__(self, username, password):
        self.username = username
        self.password = password

    @property
    def car_type(self):
        if self.username == 'john':
            return self._get_name() + ' Chevy'

foo = Parent('john', 'passwd')
print foo.child_action().car_type

bar = Parent('joe', 'passwd')
print bar.child_action().car_type