/**
  * Save a preferred currency for a member.
  * @param EcommerceCurrency $currency - object for the currency
  */
 public function SetPreferredCurrency(EcommerceCurrency $currency)
 {
     if ($this->owner->exists()) {
         if ($currency && $currency->exists()) {
             $this->owner->PreferredCurrencyID = $currency->ID;
             $this->owner->write();
         }
     }
 }