请求库中的RequestHooksMixin类是什么？

Question

我想了解基于类的设计决策

  

RequestHooksMixin

请求库中的

。它的目的和用途是什么？

class RequestHooksMixin(object):
    def register_hook(self, event, hook):
        """Properly register a hook."""

        if event not in self.hooks:
            raise ValueError('Unsupported event specified, with event name "%s"' % (event))

        if isinstance(hook, Callable):
            self.hooks[event].append(hook)
        elif hasattr(hook, '__iter__'):
            self.hooks[event].extend(h for h in hook if isinstance(h, Callable))

    def deregister_hook(self, event, hook):
        """Deregister a previously registered hook.
        Returns True if the hook existed, False if not.
        """

        try:
            self.hooks[event].remove(hook)
            return True
        except ValueError:
            return False