public Object getValueAt(int rowIndex, int columnIndex) {
        switch(columnIndex){
            case 0:
                return pers[rowIndex].getNom();
            case 1:
                return pers[rowIndex].getNaissance();
            case 2:
                return pers[rowIndex].isMasculin();
            case 3:
                return pers[rowIndex].getPays();
            default:
                return null; //Ne devrait jamais arriver
        }
    }