How do I combine:
button.modify_bg(gtk.STATE_NORMAL, gtk.gdk.color_parse("Green"))
button.modify_bg(gtk.STATE_ACTIVE, gtk.gdk.color_parse("Green"))
button.modify_bg(gtk.STATE_SELECTED, gtk.gdk.color_parse("Green"))
etc.
Into a one-liner wildcard covering all of the possible states (See Doc)