Calculate total only of shipping products

functions.php

<?php 

add_filter('ywcm_cart_total','ywcm_cart_total');
function ywcm_cart_total( $total ){

	$total = 0;
	if ( ! empty( WC()->cart->cart_contents ) ) {
		foreach ( WC()->cart->cart_contents as $cart_item_key => $values ) {

			if ( $values['data']->needs_shipping() ) {
				$total += $values['line_total'];

			}
		}
	}
	return $total;
}