public CommodityPriceData(CommodityIdentity identity, ProductPriceDocument data)
        {
            if (null == identity)
                throw new ArgumentNullException("Parameter 'identity' must not be null.", "identity");

            if (null == data)
                throw new ArgumentNullException("Parameter 'data' must not be null.", "data");

            this.Identity = identity;
            this.Data = data;
        }
        public CommodityPriceData(CommodityIdentity identity, ProductPriceDocument data)
        {
            if (null == identity)
            {
                throw new ArgumentNullException("Parameter 'identity' must not be null.", "identity");
            }

            if (null == data)
            {
                throw new ArgumentNullException("Parameter 'data' must not be null.", "data");
            }

            this.Identity = identity;
            this.Data     = data;
        }