.selectBoxIt is not a function

[deyan4]

This is the piece of code where it is called the .selectBoxIt

    $('#productsSortForm select').selectBoxIt({
        native: true
    });
    $('.attribute_list select').selectBoxIt({
        native: true
    });

    $('#category_search select').selectBoxIt({
        native: true
    });

Prestashop 1.6.1.7.