Как в классе walker задать в внутри ссылки span?

Question

[Vinyard Rip]

<ul class="nav__list nav">
  <!-- menu__list -->
  <li class="nav__item">
    <!-- menu__item -->
    <a href="" class="nav__link js-active link-width"
      >Product #0
      <!-- menu__link -->
      <span class="js-width"></span>
      <!-- button menu__arrow -->
    </a>
    <span class="nav__arr"></span>
    <!-- 00000 -->
    <ul class="subnav__list subnav">
      <!-- menu__sub-list -->
      <li class="subnav__item">
        <!-- menu__sub-item -->
        <a href="" class="subnav__link">Product #1</a>
        <!-- menu__sub-link -->
        <ul class="sub2nav__list sub2nav">
          <!-- menu__subsub-list -->
          <li class="sub2nav__item">
            <!-- menu__subsub-item -->
            <a href="" class="sub2nav__link">Product #2</a>
            <!-- menu__subsub-link  -->
          </li>
        </ul>
      </li>
    </ul>
  </li>
</ul>

<?php
class My_Walker_Nav_Menu extends Walker_Nav_Menu
{
  // add classes to ul sub-menus
  function start_lvl(&$output, $depth = 0, $args = NULL)
  {
    // depth dependent classes
    $indent = ($depth > 0 ? str_repeat("\t", $depth) : ''); // code indent
    $display_depth = ($depth + 1); // because it counts the first submenu as 0
    $classes = array(
      '',
      ($display_depth % 2 ? 'menu-odd' : 'menu-even'),
      ($display_depth >= 2 ? 'sub2nav__list sub2nav' : 'subnav__list subnav'),
      'menu-depth-' . $display_depth
    );
    $class_names = implode(' ', $classes);

    // build html
    if ($display_depth === 0):

      //$output .= "\n" . $indent . '<span" class="nav__arr">' . "</span>"; ????? not work
      $output .= "\n" . $indent . '<ul class="' . $class_names . '">' . "\n";

    else:
      $output .= "\n" . $indent . '<ul class="' . $class_names . '">' . "\n";

    endif;
  }

  // add main/sub classes to li's and links
  function start_el(&$output, $item, $depth = 0, $args = NULL, $id = 0)
  {
    global $wp_query;
    $indent = ($depth > 0 ? str_repeat("\t", $depth) : ''); // code indent

    // depth dependent classes
    $depth_classes = array(
      ($depth == 0 ? 'nav__item' : ''),
      ($depth == 1 ? 'subnav__item' : ''),
      ($depth >= 2 ? 'sub2nav__item' : ''),
      //($depth % 2 ? 'item-odd' : 'item-even'),
      //'item-depth-' . $depth
    );
    $depth_class_names = esc_attr(implode('', $depth_classes));

    // passed classes
    $classes = empty($item->classes) ? array() : (array) $item->classes;
    $class_names = esc_attr(implode(' ', apply_filters('nav_menu_css_class', array_filter($classes), $item, $args, $depth)));

    // build html
    $output .= $indent . '<li class="' . $depth_class_names . '">';

    // link attributes
    $attributes = !empty($item->attr_title) ? ' title="' . esc_attr($item->attr_title) . '"' : '';
    $attributes .= !empty($item->target) ? ' target="' . esc_attr($item->target) . '"' : '';
    $attributes .= !empty($item->xfn) ? ' rel="' . esc_attr($item->xfn) . '"' : '';
    $attributes .= !empty($item->url) ? ' href="' . esc_attr($item->url) . '"' : '';
    $attributes .= ' class="' . ($depth == 0 ? 'nav__link js-active link-width' : '') . ($depth == 1 ? 'subnav__link' : '') . ($depth
      >= 2 ? 'sub2nav__link' : '') . '"';
    $attributes .= ($depth == 0) ? '>' . '<span class="js-width"></span></a>' : '</a>';

    $item_output = sprintf(
      //'%1$s<a%2$s>%3$s%4$s%5$s</a>%6$s',
      '<a%2$s',
      $args->before,
      $attributes,
      $args->link_before,
      apply_filters('the_title', $item->title, $item->ID),
      $args->link_after,
      $args->after
    );

    // build html
    $output .= apply_filters('walker_nav_menu_start_el', $item_output, $item, $depth, $args);
  }
}