class ProductModel(Model):
        __model_name__ = 'product.product'

        list_price = MoneyType('currency_code')

        @property
        def currency_code(self):
            return 'USD'
    class ContactModel(Model):
        __model_name__ = 'party.party'

        name = StringType()
        credit_limit_amount = MoneyType('currency_code')

        @property
        def currency_code(self):
            return 'USD'
    class SaleOrderModel(Model):
        __model_name__ = 'sale.sale'
        _eager_fields = set(['currency.code'])

        number = StringType()
        total_amount = MoneyType('currency_code')

        @property
        def currency_code(self):
            return self._values['currency.code']