public virtual void SaveAttribute<TPropType>(BaseEntity entity, string key, TPropType value, int storeId = 0)
        {
            if (entity == null)
                throw new ArgumentNullException("entity");

            if (key == null)
                throw new ArgumentNullException("key");

            string keyGroup = entity.GetUnproxiedEntityType().Name;

            var props = GetAttributesForEntity(entity.Id, keyGroup)
                .Where(x => x.StoreId == storeId)
                .ToList();
            var prop = props.FirstOrDefault(ga =>
                ga.Key.Equals(key, StringComparison.InvariantCultureIgnoreCase)); //should be culture invariant

            var valueStr = CommonHelper.To<string>(value);

            if (prop != null)
            {
                if (string.IsNullOrWhiteSpace(valueStr))
                {
                    //delete
                    DeleteAttribute(prop);
                }
                else
                {
                    //update
                    prop.Value = valueStr;
                    UpdateAttribute(prop);
                }
            }
            else
            {
                if (!string.IsNullOrWhiteSpace(valueStr))
                {
                    //insert
                    prop = new GenericAttribute
                    {
                        EntityId = entity.Id,
                        Key = key,
                        KeyGroup = keyGroup,
                        Value = valueStr,
                        StoreId = storeId,

                    };
                    InsertAttribute(prop);
                }
            }
        }