Remove the observers of the observers list.
        It will not receive any more notifications when occurs changes.

        :param UpdatesObserver observer: Observer you will not receive any more notifications then
                                         occurs changes.

def unregister(self, observer):
        """
        Remove the observers of the observers list.
        It will not receive any more notifications when occurs changes.

        :param UpdatesObserver observer: Observer you will not receive any more notifications then
                                         occurs changes.
        """
        self.observer_manager.observers.remove(observer)
        observer.manager = None