code: def add_widget(self, widget, column=0):
          
          # Make sure that the Layout is fully initialised before we try to add any widgets.
          if self._frame is None:
              raise RuntimeError("You must add the Layout to the Frame before you can add a Widget.")
  
          # Now process the widget.
          self._columns[column].append(widget)
          widget.register_frame(self._frame)
  
          if widget.name in self._frame.data:
              widget.value = self._frame.data[widget.name]
docs: Add a widget to this Layout.
  
          If you are adding this Widget to the Layout dynamically after starting to play the Scene,
          don't forget to ensure that the value is explicitly set before the next update.
  
          :param widget: The widget to be added.
          :param column: The column within the widget for this widget.  Defaults to zero.