### 2.9.3 Propagating changes from Model to Proxy

In our previous example, our model was defined as an instance of a simple Python class. If we use the complete framework, by having our model classes inherit from `FrameWork.Model`, we also get reverse notifications from Model to Proxy: when the model is altered, the change propagates to the proxy interface attached to it.

To demonstrate, we can extend the example above to add a "reset" button to trigger a change of the model; we will subclass ProxyDelegate (which is also a Delegate, as stated before, and thus supports the special handler syntax `on_*()`) to define a handler for clicking on the reset button (examples/framework/newsform/newsform2.py):

If we look at the handler for reset, `on_reset__clicked()`, we can see it alters the model directly. These changes reflect automatically in the interface by means of an update mechanism present in `FrameWork.Model`. This holds true no matter what function triggers the change in the model: it is not limited to callbacks defined in Proxy itself; any handler that alters the model will trigger the model's update mechanism.

In summary: if you need to alter your model independently of the interface, have your model inherit from FrameWork.Model and enjoy automatic UI updating.

In all the examples we have shown up to now, you may notice that the proxy manipulates the model's instance variables directly. There are times where this is not desirable, and the next section explains how to customize the proxy and model's behavior.