title: Some actions with object in UpdateAPIView when update
body: <p>My code:</p>
  
  <pre><code>class CarView(generics.UpdateAPIView):
      permission_classes = (IsAdminUser,)
      serializer_class = CarSerializer
  
      def get_queryset(self):
          return ...
  
      def update(self, request, *args, **kwargs):
          # some actions
          return super(CarView, self).update(request, *args, **kwargs) 
  </code></pre>
  
  <p>In update method I want to do some operations with updated object. How to do this?</p>