public Reply doComputation() {
		int result = -666;
		if (this.operand.equals("+")) {
			result = this.firstValue + this.secondValue;
		} else if (this.operand.equals("-")) {
			result = this.firstValue - this.secondValue;
		} else if (this.operand.equals("*")) {
			result = this.firstValue * this.secondValue;
		} else if (this.operand.equals("fib")) {
			result = fib(this.firstValue);
		} else {
			throw new IllegalArgumentException(
					"Not applicable for this operation");
		}
		return new Reply(result);
	}