/**
  * update_claimed_stock method
  * Updates the claimed stock table, to prevent people from having more than the existing stock in their carts
  * @access public
  *
  * no parameters, nothing returned
  */
 function update_claimed_stock()
 {
     global $wpdb;
     if ($this->has_limited_stock == true) {
         $claimed_query = new WPSC_Claimed_Stock(array('product_id' => $this->product_id, 'cart_id' => $this->cart->unique_id));
         $claimed_query->update_claimed_stock($this->quantity);
     }
 }