PyQT QSqlRelationalDelegate Combobox -

i have form has qtableview qsqlrelationaltablemodel. 2 of columns read only, 1 combobox , 1 spinbox specific range (no negative numbers.)

out of box without qsqlrelationaldelegate, view works combobox automatically on third column , spinbox. in trying put validation in spinbox, found solved readonly problem on first 2 columns. problem how correctly implement combobox on related field foreign key. have been able combobox display can't see how populate choices foreign keys.

how populate combo box?

see code

    def setup_rates_view(self):         self.rates_model = qsqlrelationaltablemodel(self)         self.rates_model.settable("rates_stay")         self.rates_model.setrelation(6, qsqlrelation("rates", "rate_code", "rate_description"))         self.rates_model.setfilter("id_bookings = '{0}'".format(myapp.res_id))         self.rates_model.setheaderdata(1, qt.horizontal, "date")         self.rates_model.setheaderdata(2, qt.horizontal, "basis")         self.rates_model.setheaderdata(6, qt.horizontal, "code")         self.rates_model.setheaderdata(4, qt.horizontal, "amount")         self.rates_model.select()         self.rates_view = self.ui.rates         self.rates_view.setmodel(self.rates_model)         self.rates_view.setitemdelegate(qsqlrelationaldelegate(self.rates_view))         self.rates_view.setcolumnhidden(0, true)         self.rates_view.setcolumnhidden(3, true)         self.rates_view.setcolumnhidden(5, true)         self.rates_view.horizontalheader().movesection(4,6)         self.rates_view.resizecolumnstocontents()         self.rates_view.setitemdelegate(viewrates(self))  class viewrates(qsqlrelationaldelegate):     def __init__(self, parent=none):         qitemdelegate.__init__(self)       def createeditor(self, parent, option, index):         if index.column() == 4:             spinbox = qspinbox(parent)             spinbox.setrange(0,10000)             return spinbox         elif index.column() == 6:             combo = qcombobox(parent)             combo.setmodel()             return combo