def del tkar_id
      tkaroid = @objects[tkar_id]
      if tkaroid
        if @follow_id == tkar_id
          follow nil
        end
        delete tkaroid.tag
        @objects.delete tkar_id
        @changed.delete tkar_id
        get_objects_by_layer(tkaroid.layer).delete tkaroid
      end
    end
def del tkar_id
      tkaroid = @objects[tkar_id]
      if tkaroid
        if @follow_id == tkar_id
          follow nil
        end
        delete tkaroid.tag
        @objects.delete tkar_id
        @changed.delete tkar_id
        get_objects_by_layer(tkaroid.layer).delete tkaroid
      end
    end
Not "delete"! That already exists in tk.