public function getFlatShippingRates(Country_Shipping $country)
 {
     //Get valid rates for this country
     $countryID = $country && $country->exists() ? $country->ID : null;
     $rates = FlatFeeShippingRate::get()->filter("CountryID", $countryID);
     $this->extend("updateFlatShippingRates", $rates, $country);
     return $rates;
 }