The GObject methods set_data() and get_data() allow you to attach an arbitrary reference to a GObject (or any derived class) instance keyed by a string. In other words, you can attach any number of references to any GObject and retrieve them with the strings you set() them with. This is a very helpful but often overlooked feature of GTK+, and it can come in handy.

For example, you can attach to a GtkLabel the instance it represents and a list of of versions using the following code:

 l = gtk.Label()
 l.set_data("object-name", some_object)

and then retrieve the data using:

 >>> some_object = l.get_data("object-name")

There are also related methods associated with the CList/CTree, set/get_row_data(), and GnomeIconList's set/get_icon_data(). These methods don't index on string, but instead on position in their internal arrays.