/**
  * @param ReservationSeries $reservationSeries
  * @return ReservationRuleResult
  */
 public function Validate($reservationSeries)
 {
     $resources = Resources::GetInstance();
     $errorMessage = new StringBuilder();
     $result = $this->attributeService->Validate(CustomAttributeCategory::RESERVATION, $reservationSeries->AttributeValues());
     $isValid = $result->IsValid();
     foreach ($result->Errors() as $error) {
         $errorMessage->AppendLine($error);
     }
     if (!$isValid) {
         $errorMessage->PrependLine($resources->GetString('CustomAttributeErrors'));
     }
     return new ReservationRuleResult($isValid, $errorMessage->ToString());
 }