Genesis: Add classes to Genesis Navigation

functions.php

/*
 * Add classes to Genesis Navigation
 *
 */
add_filter( 'genesis_do_nav', 'webendev_override_do_nav', 10, 3 );
function webendev_override_do_nav($nav_output, $nav, $args) {

	$args['menu_id'] = 'the_id_you_want';
	$args['menu_class'] = 'class1 class2'; // replace what was there
	$args['menu_class'] .= ' nav-bar'; // or append to it

	if ( genesis_get_option( 'nav' ) ) {
		if ( has_nav_menu( 'primary' ) ) {
			$nav = wp_nav_menu( $args );
		} elseif ( 'nav-menu' != genesis_get_option( 'nav_type', 'genesis-vestige' ) ) {
			$nav = genesis_nav( $args );
		}
	}

	return sprintf( '<div id="nav">%2$s%1$s%3$s</div>', $nav, genesis_structural_wrap( 'nav', 'open', 0 ), genesis_structural_wrap( 'nav', 'close', 0 ) );
}