def get_rates(self):
"""
Return list of tuples as:
[
(<display method name>, <rate>, <currency>, <metadata>)
...
]
"""
Sale = Pool().get('sale.sale')
sale = Transaction().context.get('sale')
if sale and self.carrier_cost_method == 'ups':
sale = Sale(sale)
sale.carrier = self
return sale.get_ups_shipping_rates()
return super(Carrier, self).get_rates()
