code: def showAddColumnDialog(self, triggered):
          
          if triggered:
              dialog = AddAttributesDialog(self)
              dialog.accepted.connect(self.addColumn)
              dialog.rejected.connect(self.uncheckButton)
              dialog.show()
docs: Display the dialog to add a column to the model.
  
          This method is also a slot.
  
          Args:
              triggered (bool): If the corresponding button was
                  activated, the dialog will be created and shown.