Chapter 6: PostViewSet.perform_create creates an object twice

[achraibi]

perform_create creates a Post object by invoking save on the serializer and passing the author as an argument. Why would we need to call the parent perform_create (which calls update since instance is not None) ?

def perform_create(self, serializer):
    instance = serializer.save(author=self.request.user)
    return super(PostViewSet, self).perform_create(serializer)