private void When(PriceListItemAttributesChangedDomainEvent @event)
 {
     this._countryCode        = @event.CountryCode;
     this._subscriptionPeriod = SubscriptionPeriod.Of(@event.SubscriptionPeriodCode);
     this._category           = PriceListItemCategory.Of(@event.CategoryCode);
     this._price = MoneyValue.Of(@event.Price, @event.Currency);
 }
 private void When(PriceListItemCreatedDomainEvent @event)
 {
     this.Id             = @event.PriceListItemId;
     _countryCode        = @event.CountryCode;
     _subscriptionPeriod = SubscriptionPeriod.Of(@event.SubscriptionPeriodCode);
     _category           = PriceListItemCategory.Of(@event.CategoryCode);
     _price    = MoneyValue.Of(@event.Price, @event.Currency);
     _isActive = true;
 }