Copy and synchronice a WooCommerce product programmatically with Polylang from frontend

polylang_pro_synchronize_wc_product.php

<?php
/**
 * I had a hard time accessing the Polylang PLL_Admin methods from the frontend. Instantiating classes manually didnt work.
 * Luckily the Polylang boss jumped in and provided this solution. This shold also be working with other Polylang methods
 * that can normally only be executed from admin side.
*/ 
$pll = new PLL_Admin( PLL()->links_model );
$pll->add_filters();
$pll_pro = new Polylang_Pro();
$pll_pro->load_modules( $pll );

$pll->sync_post->copy_post( $post_id, $lang, true);


/* Description of the copy_post method
        /**
         * Duplicates the post to one language and optionally saves the synchronization group
         *
         * @since 2.2
         *
         * @param int    $post_id    Post id of the source post
         * @param string $lang       Target language
         * @param bool   $save_group True to update the synchronization group, false otherwise
         * @return int Post id of the target post
         */
        public function copy_post( $post_id, $lang, $save_group = true ) 
*/