def move_layer_down(self):
        """Move the layer down."""
        layer = self.list_layers_in_map_report.selectedItems()[0]
        index = self.list_layers_in_map_report.indexFromItem(layer).row()
        item = self.list_layers_in_map_report.takeItem(index)
        self.list_layers_in_map_report.insertItem(index + 1, item)
        self.list_layers_in_map_report.item(index + 1).setSelected(True)
Move the layer down.