You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: CEC2008_F4.m
    path of file: ./repos/PlatEMO/PlatEMO/Problems/Single-objective optimization/CEC 2008
    
    the code of the file until where you have to start completion: classdef CEC2008_F4 < PROBLEM
% <single> <real> <large/none> <expensive/none>
% Shifted Rastrign's function

%------------------------------- Reference --------------------------------
% K. Tang, X. Yao, P. N. Suganthan, C. MacNish, Y.-P. Chen, C.-M. Chen, and
% Z. Yang, Benchmark functions for the CEC'2008 special session and
% competition on large scale global optimization, Nature Inspired
% Computation and Applications Laboratory, USTC, China, 2007.
%------------------------------- Copyright --------------------------------
% Copyright (c) 2023 BIMK Group. You are free to use the PlatEMO for
% research purposes. All publications which use this platform or any code
% in the platform should acknowledge the use of "PlatEMO" and reference "Ye
% Tian, Ran Cheng, Xingyi Zhang, and Yaochu Jin, PlatEMO: A MATLAB platform
% for evolutionary multi-objective optimization [educational forum], IEEE
% Computational Intelligence Magazine, 2017, 12(4): 73-87".
%--------------------------------------------------
    
function

%------------------------------- Reference --------------------------------
% K. Tang, X. Yao, P. N. Suganthan, C. MacNish, Y.-P. Chen, C.-M. Chen, and
% Z. Yang, Benchmark functions for the CEC'2008 special session and
% competition on large scale global optimization, Nature Inspired
% Computation and Applications Laboratory, USTC, China, 2007.
%------------------------------- Copyright --------------------------------
% Copyright (c) 2023 BIMK Group. You are free to use the PlatEMO for
% research purposes. All publications which use this platform or any code
% in the platform should acknowledge the use of "PlatEMO" and reference "Ye
% Tian, Ran Cheng, Xingyi Zhang, and Yaochu Jin, PlatEMO: A MATLAB platform
% for evolutionary multi-objective optimization [educational forum], IEEE
% Computational Intelligence Magazine, 2017, 12(4): 73-87".
%--------------------------------------------------------------------------

    properties
        O;  % Optimal decision vector
    end
    methods
        %% Default settings of the problem
        function Setting(obj)
            CallStack = dbstack('-completenames');
            load(fullfile(fileparts(CallStack(1).file),'CEC2008.mat'),'Data');
            obj.O = Data{4};
            obj.M = 1;
            if isempty(obj.D); obj.D = 100; end