private boolean computeDoubleExperssion(double value1, double value2) throws NumberFormatException  {
        boolean result;
        if (this.oper.equals(">=")) {
            result = value1 >= value2;
        } else if (this.oper.equals("<=")) {
            result = value1 <= value2;
        } else if (this.oper.equals(">")) {
            result = value1 > value2;
        } else if (this.oper.equals("<")) {
            result = value1 < value2;
        } else {
            result = false;
        }
        return result;
    }