title: How can I add class to <a href> wp_nav_menu?
body: <p>I have 2 menu. How can I add class to a href for 'header_menu'? Thanks</p>
  
  <pre><code>function register_menus() {
      register_nav_menus(
          array(
              'header_menu'      =&gt; 'Header menu',
              'header_menu_page' =&gt; 'Menu Page'           
  
          )
      );
  }
  }
  add_action( 'after_setup_theme', 'register_menus' );
  </code></pre>