How to load two ARFF file in Matlab?

I want to load ARFF file to matlab and i find this function

    function wekaOBJ = loadARFF(filename)

    import weka.core.converters.ArffLoader;
    import java.io.File;

    loader = ArffLoader();
    loader.setFile(File('train.arff'));
    wekaOBJ = loader.getDataSet();
    wekaOBJ.setClassIndex(wekaOBJ.numAttributes -1);

    end
But when i try to load 2 ARFF files with this code i only get the last file.How can i solve this ?

    function wekaOBJ = loadARFF(filename)
    import weka.core.converters.ArffLoader;
    import java.io.File;

    loader = ArffLoader();
    loader.setFile(File('train.arff'));
    wekaOBJ = loader.getDataSet();
    wekaOBJ.setClassIndex(wekaOBJ.numAttributes -1);
    loader = ArffLoader();
    loader.setFile(File('test.arff'));
    wekaOBJ = loader.getDataSet();
    wekaOBJ.setClassIndex(wekaOBJ.numAttributes -1);

    end