/**
  * Build the $data-array
  *
  * @param extension $system
  */
 public function __construct(extension &$system)
 {
     parent::__construct($system);
     $this->data['costs'] =& $this->costs;
     $this->data['sum'] =& $this->sum;
     $this->data['product'] =& $this->product;
     $this->data['total'] =& $this->total;
 }
 public function __construct(extension &$system)
 {
     parent::__construct($system);
 }