public function clear_doubles(){
        $query = $this->db->query("SELECT * FROM `oc_product` WHERE xml_id IN ( SELECT xml_id FROM `oc_product` GROUP BY `xml_id` HAVING COUNT( `xml_id` ) > 1 ) ORDER BY `oc_product`.`xml_id` ASC");

        $doubles = $query->num_rows != 0 ? $query->rows : [];

        $original = array_shift($doubles);

        foreach($doubles as $double){
            var_dump($original['xml_id'], $double['xml_id']); echo "<br>";

            $this->load->model('catalog/product');

            if($original['xml_id'] == $double['xml_id']){
                echo "delete ".$double['product_id']." double of ".$original['product_id']."<br>";
                $this->model_catalog_product->deleteProduct($double['product_id']);
            }else{
                $original['xml_id'] = $double['xml_id']; continue;
            }
        }
    }