code: def change_background(color):
      
      viewer.widget.background_color = colors.any_to_rgb(color)
      viewer.update()
docs: Setup the background color to *color*. 
      
      Example::
  
        change_background('black')
        change_background('white')
        change_background('#ffffff')
      
      You can call this function interactively by using::
  
          change_color.interactive()
      
      A new dialog will popup with a color chooser.
  
  
      .. seealso:: :py:func:`chemlab.graphics.colors.parse_color`