Why we use super().perform_update(serialixer) when we redefining methods?

General
1

Why we use super().perform_update(serializer)? But not serializer.save() ? What’s the difference?

def perform_update(self, serializer):
        if serializer.instance.author != self.request.user:
            raise PermissionDenied('Сhange other people\'s content forbidden')
        super(PostViewSet, self).perform_update(serializer)
        #serializer.save()