[pygtk] How do I get the previous gtk.TreeIter in a TreeModel?

[Rich Burridge]

Hi,

Hopefully I'm missing something obvious.

Given a gtk.TreeIter in a gtk.TreeModel, from:

http://www.pygtk.org/docs/pygtk/class-gtktreemodel.html#method-gtktreemodel--iter-next

I can see how to get the gtk.TreeIter pointing to the next row.
But how to I get a gtk.TreeIter pointing to the previous row?

Just in case I'm taking the wrong approach here, what I want to do is move
one (or more) selected rows, up one row.

I was expecting the code for the callback for the "Move up one" button
to be something like:

    def textMoveUpOneButtonClicked(self, widget):
        textSelection = self.getTextAttributesView.get_selection()
        [model, paths] = textSelection.get_selected_rows()
        for path in paths:
            iter = model.get_iter(path)
            prevIter = model.iter_prev(iter)
            model.swap(iter, prevIter)

but there is no gtk.TreeMode.iter_prev() function.