public static QueryProperty NotEq <T>(this QueryProperty property, T operand)
        {
            AddExpression(property, "$ne", QueryOperator.ConvertOperandToJson <T>(operand).ToString());
            //AddExpression(property, "$ne",
            //    operand is string ?
            //        string.Format("'{0}'", operand) :
            //        operand.ToString());

            return(property);
        }