def cauldron_extras(self):
        """ Yield extra tuples containing a field name and a callable that takes
        a row
        """
        for extra in super(Dimension, self).cauldron_extras:
            yield extra

        if self.formatters:
            prop = self.id + '_raw'
        else:
            prop = self.id_prop

        yield self.id + '_id', lambda row: getattr(row, prop)
Yield extra tuples containing a field name and a callable that takes
        a row