[PyMOL] select/deselecting objects via script?

[Jacob Corn]

I'd like to write a jiffy that binds the up and down arrow keys to  
move up/down the list in the object/selection pane. I'd like (for  
example) pressing the down arrow to equate to clicking the currently  
active object (thus hiding its representation) and clicking the next  
object down (thus showing it). That way, none of the various cartoon/ 
stick/spheres are lost, but the current object disappears and the next  
one appears. What is the pymol command for choosing/un-choosing [sic]  
something in the right-hand panel?

Jacob