Root window outside of current program

[root]

Hi, I have a program that when it is launched I save the ID of the
window using the winfo_id() method out to a file.  Does anyone out there
know if it's possible to bring the previously launched window into focus
using the ID saved, but now being called from another python app.  This
is being done from X in Gnome, if that is any help.  It seems like it
should be doable, but I can't find a starting point.   Any help would be
appreciated.

Thanks,

Rob P.