我想从ul class=“sub-ul”的li标签中删除2级深度的一个类。我怎样才能用Walker做到这一点?
<ul class="navigation d-block">
<li class="d-inline-block">
<a href="#" class="active">About</a>
<ul class="sub-ul">
<li><a href="#">Mission & vision</a></li>
<li><a href="#">Mission & vision</a></li>
<li><a href="#">Mission & vision</a></li>
<li><a href="#">Mission & vision</a></li>
<li><a href="#">Mission & vision</a></li>
<li><a href="#">Mission & vision</a></li>
<li><a href="#">Mission & vision</a></li>
</ul>
</li>
<li class="d-inline-block">
<a href="#">For patients</a>
</li>
<li class="d-inline-block">
<a href="#">Activities</a>
</li>
<li class="d-inline-block">
<a href="#">Project</a>
</li>
<li class="d-inline-block">
<a href="#">Event</a>
</li>
</ul>
<?php
//Show the navigation menu
wp_nav_menu(array(
\'theme_location\' => \'primary-nav\',
\'menu_class\' => \'navigation d-block\',
\'walker\' => new My_Walker_Nav_Menu()
));
?>