Set shipping class based on Tag or Attribute Woocommerce

Question

I need to update Shipping class based on Tag, example all products with tag "Fresh" shoud have shipping class "fresh" . i try this, but without results..

add_action( 'admin_init', 'action_woocommerce_init_3', 10, 1 );
function action_woocommerce_init_3( $array ) {
/** The shipping class to set for the products */
$shipping_class_slug = "fresh"; // found in "shipping classes" in woocommerce settings

/** Run query to collect our data */
$products = new WP_Query(array(
    'post_type' => 'product',
    'posts_per_page' => -1,
    'tax_query' => array(
        array(
            'taxonomy'        => 'post_tag',
            'field'           => 'term_id',
            'terms'           => 'fresh',
            'field'           => 'slug',
            'operator'        => 'IN'
        ) 
    )
) );
/** Set our shipping class on each product */
foreach ($products->posts as $pid) {
    wp_set_object_terms($pid, $shipping_class_slug, 'product_shipping_class');
}
/** reset the query */
wp_reset_query() ;};

I use this code for update shipping class based on category and it's working

add_action( 'admin_init', 'action_woocommerce_init', 10, 1 );
function action_woocommerce_init( $array ) { 
$category_ids = array(181, 183, 1690);
$shipping_class_slug = "free";
/** Run query to collect our data */
$products = new WP_Query(array(
    'post_type' => 'product',
    'posts_per_page' => -1,
    'fields' => 'ids',
    'tax_query' => array(
        array(
            'taxonomy' => 'product_cat',
            'field' => 'term_id',
            'terms' => $category_ids,
            'operator' => 'IN'
        )
    )
));

/** Set our shipping class on each product */
foreach ($products->posts as $pid) {
    wp_set_object_terms($pid, $shipping_class_slug, 'product_shipping_class');
}

/** reset the query */
wp_reset_query();};