code: def model_changed(self, model):
          
          self.setModel(model)
          # to update all lists belwo
          # current changed is not triggered by setModel somehow
          if model is not None:
              self.setCurrentIndex(self.model().index(0, 0))
docs: Apply the model to the combobox
  
          When a level instance is created, the model is None. So it has to be set afterwards.
          Then this method will be called and your level should somehow use the model
  
          :param model: the model that the level should use
          :type model: QtCore.QAbstractItemModel
          :returns: None
          :rtype: None
          :raises: None