GtkCellLayoutDataFunc to use for cell.layout. This function
is used instead of the standard attributes mapping for setting the
column value, and should set the value of cell.layout's cell renderer(s)
as appropriate. func may be NULL to remove and older one.gtkCellLayoutSetCellDataFunc(object, cell, func, func.data = NULL)objectcellfuncGtkCellLayoutDataFunc to use.func.datafunc.