::
        
            GET /:login/machines/:id/snapshots/:name
        
        Fetch the existing state and values for the snapshot 
        and commit the values locally.

def refresh(self):
        """
        ::
        
            GET /:login/machines/:id/snapshots/:name
        
        Fetch the existing state and values for the snapshot 
        and commit the values locally.
        """
        data = self.machine.raw_snapshot_data(self.name)
        self._save(data)