如何在一个类中删除事件监听器？

Question

说我有一个类，其中包含一些方法，例如：

# I'm assuming here a couple of things:
# The fields content and date_created exist in your Letter model, 
# if there is no date created field, use instead whatever you are using for
# establish some sort of order creation.
MailBox.objects.annotate(
    last_letter_content = Subquery(
        Letter.objects.filter(mailbox=OuterRef('pk')).order_by('-date_created').values('content')[:1]
    )
)

调用removeClickListener不会删除事件侦听器。是因为自我每次都在改变吗？有没有办法在类构造函数中分配self，然后在侦听器参数的匿名函数中引用它？