code: def on_lstUnits_itemSelectionChanged(self):
          
          self.clear_further_steps()
          # Set widgets
          unit = self.selected_unit()
          # Exit if no selection
          if not unit:
              return
          self.lblDescribeUnit.setText(unit['description'])
          # Enable the next button
          self.parent.pbnNext.setEnabled(True)
docs: Update unit description label and field widgets.
  
          .. note:: This is an automatic Qt slot
             executed when the unit selection changes.