How colud I solve this problem Undefined function 'fitPosterior' for input arguments of type 'classreg.​learning.p​artition.C​lassificat​ionPartiti​onedModel'​.

t1=cellstr(num2str(t));
md1SVM = fitcsvm(sFeat,t1,'Standardize',true,'Kfold',10,'KernelFunction','gaussian');
% md1SVM = crossval(md1SVM);
 Md1 = fitPosterior(md1SVM);
[~,score_svm] = resubPredict(Md1);
 [Xsvm,Ysvm,Tsvm,AUCsvm] = perfcurve(trainlabel,score_svm(:,Md1.ClassNames),'true');