tree.model and iter. That is, for
every attribute mapping in tree.column, it will get a value from the set
column on the iter, and use that value to set the attribute on the cell
renderer. This is used primarily by the GtkTreeView.gtkTreeViewColumnCellSetCellData(object, tree.model, iter, is.expander, is.expanded)objecttree.modelGtkTreeModel to to get the cell renderers attributes from.iterGtkTreeIter to to get the cell renderer's attributes from.is.expanderTRUE, if the row has childrenis.expandedTRUE, if the row has visible children