我正在自学wordpress，这是html模板的代码。

    <div class="collapse navbar-collapse" id="ftco-nav">
        <ul class="navbar-nav ml-auto">
            <li class="nav-item active"><a href="index.html" class="nav-link">Home</a></li>
            <li class="nav-item"><a href="about.html" class="nav-link">Who we are</a></li>
            <li class="nav-item"><a href="causes.html" class="nav-link">Causes</a></li>
            <li class="nav-item"><a href="blog.html" class="nav-link">Stories</a></li>
            <li class="nav-item"><a href="contact.html" class="nav-link">Contact</a></li>
        </ul>
    </div>

我想把它转换成wordpress。我通过添加以下代码将其转换为wordpress：-

<?php wp_nav_menu(array( \'menu\' => \'primary\', \'container\' => \'div\', \'container_class\' => \'collapse navbar-collapse\', \'container_id\' => \'ftco-nav\', \'menu_class\' => \'navbar-nav ml-auto\', \'menu_id\' => \'\', ));?>

但问题是，如何将活动类应用于它？请有人帮我一下。

function add_active_class_to_menu_item($classes, $item) {
    if (in_array(\'current-menu-item\', $classes) ){
        $classes[] = \'active \';
    }
    return $classes;
}
add_filter(\'nav_menu_css_class\' , \'add_active_class_to_menu_item\' , 10 , 2);