/**
  * Increase stock level of the product
  *
  * @param   int		$by		Amount to increase by
  */
 function increase_stock($by = 1)
 {
     global $woocommerce;
     if ($this->variation_has_stock) {
         if ($this->managing_stock()) {
             $this->stock = $this->stock + $by;
             $this->total_stock = $this->total_stock + $by;
             update_post_meta($this->variation_id, '_stock', $this->stock);
             $woocommerce->clear_product_transients($this->id);
             // Clear transient
             // Parents out of stock attribute
             if ($this->is_in_stock()) {
                 update_post_meta($this->id, '_stock_status', 'instock');
             }
             return $this->stock;
         }
     } else {
         return parent::increase_stock($by);
     }
 }
 /**
  * Increase stock level of the product.
  *
  * @param int $by (default: 1) Amount to increase by
  * @return int stock level
  */
 public function increase_stock($by = 1)
 {
     if ($this->variation_has_stock) {
         return $this->set_stock($this->stock + $by);
     } else {
         return parent::increase_stock($by);
     }
 }
 /**
  * Increase stock level of the product
  *
  * @param   int		$by		Amount to increase by
  */
 function increase_stock($by = 1)
 {
     if ($this->variation_has_stock) {
         if ($this->managing_stock()) {
             $this->stock = $this->stock + $by;
             $this->total_stock = $this->get_total_stock() + $by;
             update_post_meta($this->variation_id, '_stock', $this->stock);
             // Parents out of stock attribute
             if ($this->is_in_stock()) {
                 update_post_meta($this->id, '_stock_status', 'instock');
             }
             return $this->stock;
         }
     } else {
         return parent::increase_stock($by);
     }
 }