Set Woocommerce Product Attribute

set_product_attribute.php

<?php
public function set_product_attribute($taxonomy, $terms, $isvariation = true)
{

   $taxonomyName = $this->taxonomy_create($taxonomy);
   $terms = explode('|', $terms);

   $term_ids = [];
   foreach ($terms as $term_name) {
      $term_name = mb_substr($term_name, 0, 200);
      if (!empty($term_name)) {
         $term_slug = sanitize_title($term_name);
         if (!term_exists($term_name, $taxonomyName)) {
            $term_data = wp_insert_term($term_name, $taxonomyName);
            $term_id = $term_data['term_id'];
         } else {
            $term_id = get_term_by('name', $term_name, $taxonomyName)->term_id;
         }
         $term_ids[] = $term_id;
      }
   }

   $attribute = new WC_Product_Attribute();
   $attribute->set_id(wc_attribute_taxonomy_id_by_name($taxonomyName));
   $attribute->set_name($taxonomyName);
   $attribute->set_options($term_ids);

   //$attribute->set_position(sizeof($attributes) + 1);
   $attribute->set_visible(true);
   $attribute->set_variation($isvariation);

   return $attribute;
}