Add custom menu location

function wpb_custom_new_menu() {
  register_nav_menus(
    array(
      'menu_1' => __( 'My Menu 1' ),
      'menu_2' => __( 'My Menu 2' )
    )
  );
}
add_action( 'init', 'wpb_custom_new_menu' );

wp_nav_menu( array( 'theme_location'=>'menu_1', 'container_class'=>'myClass' ) );