function woo_add_cart_fee() {

    global $woocommerce;
    $cart = $woocommerce->cart->cart_contents;
    foreach ($cart as $key => $item ) {
    //var_dump($item);
    $itemClass = wp_get_post_terms($item->post_parent, 'product_shipping_class');
    var_dump($itemClass);
    $itemClass->slug;
    }
}
add_action( 'woocommerce_before_calculate_totals', 'woo_add_cart_fee' );