from Subject import Subject


class Observer(object):

    def __init__(self, subject):
        assert isinstance(subject, Subject)
        self.subject = subject
        self.subject.attach(self)

    def __del__(self):
        if self in self.subject.observers:
            self.subject.detach(self)

    def update(self, **kwargs):
        raise NotImplementedError()

50d64ff7c264bdd4c63434e03f6deb2c401f70f3
<mask token>


class Observer(object):
    <mask token>
    <mask token>
    <mask token>

<mask token>


class Observer(object):

    def __init__(self, subject):
        assert isinstance(subject, Subject)
        self.subject = subject
        self.subject.attach(self)

    def __del__(self):
        if self in self.subject.observers:
            self.subject.detach(self)
    <mask token>

<mask token>


class Observer(object):

    def __init__(self, subject):
        assert isinstance(subject, Subject)
        self.subject = subject
        self.subject.attach(self)

    def __del__(self):
        if self in self.subject.observers:
            self.subject.detach(self)

    def update(self, **kwargs):
        raise NotImplementedError()

from Subject import Subject


class Observer(object):

    def __init__(self, subject):
        assert isinstance(subject, Subject)
        self.subject = subject
        self.subject.attach(self)

    def __del__(self):
        if self in self.subject.observers:
            self.subject.detach(self)

    def update(self, **kwargs):
        raise NotImplementedError()
