wordpress自定义菜单间添加分隔符

<?php if ( has_nav_menu( 'menu-1' ) ) : ?>
                <?php
                $nav = wp_nav_menu(
                    array(
                        'container'         => '',
                        'theme_location'    => 'menu-1',
                        'menu_class'     => 'menu',
                        'items_wrap'     => '<ul id="%1$s" class="%2$s">%3$s</ul>',
                        'echo' => false,
                    )
                );
                echo str_replace('</li>','</li><i class="line"></i>', $nav);
                ?>
            <?php endif; ?>