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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def set_amount_cb(self, widget, val):
 """This method is called when 'Zoom Amount' control is adjusted. """

        self.zoom_amount = val
        zoomlevel = self.fitsimage_focus.get_zoom()
        self._zoomset(self.fitsimage_focus, zoomlevel)