/**
  *
  * @param EE_Registration $registration
  */
 public function __construct($registration)
 {
     parent::__construct(array($registration));
 }
 /**
  * EE_Billable_Line_Item_Filter constructor.
  * @param EE_Registration[] $registrations
  */
 public function __construct($registrations)
 {
     parent::__construct($this->_remove_unbillable_registrations($registrations));
 }