code: def reset(self):
          
          # Ensure that the widgets are using the right values.
          self.update_widgets()
  
          # Reset all the widgets.
          for column in self._columns:
              for widget in column:
                  widget.reset()
                  widget.blur()
  
          # Find the focus for the first widget
          self._live_widget = -1
          self._find_next_widget(1)
docs: Reset this Layout and the Widgets it contains.