code: def on_lstClassifications_itemSelectionChanged(self):
          
          self.clear_further_steps()
          classification = self.selected_classification()
          # Exit if no selection
          if not classification:
              return
          # Set description label
          self.lblDescribeClassification.setText(classification["description"])
          # Enable the next button
          self.parent.pbnNext.setEnabled(True)
docs: Update classification description label and unlock the Next button.
  
          .. note:: This is an automatic Qt slot
             executed when the field selection changes.