vendor_tag_id

/*From the plugin woocommerce product vendors' file woocommerce-product-vendors-functions.php line 73 forward the function get_vendor I deducted that I by calling the global $wc_products_vendors I might be able to gain the tag_id by * doing so:
*/
global $wc_products_vendors;

$vendor = get_term( $user_id, $wc_product_vendors->token );
$tag_id = $vendor->term_id;

/*
* but I get no response on $tag_id...
* Any suggestions ? please!
*/