bool IUserType.Equals(object x, object y)
        {
            if (x == null || y == null)
            {
                return(false);
            }
            ListSet xl = (ListSet)x;
            ListSet yl = (ListSet)y;

            if (xl.Count != yl.Count)
            {
                return(false);
            }
            Boolean retvalue = xl.Minus(yl).Count == 0;

            return(retvalue);
        }