public function getLabel(\core_kernel_classes_Resource $delivery, $label = '')
    {
        $user = \common_session_SessionManager::getSession()->getUser();
        $customLabelRoles = $this->getOption(self::PROPERTY_CUSTOM_LABEL);
        if (array_intersect($customLabelRoles, $user->getRoles())) {
            $property = $this->getProperty(self::PROPERTY_CUSTOM_LABEL);
            if ((string)$delivery->getOnePropertyValue($property)) {
                $label = $delivery->getOnePropertyValue($property);
            }
        }
        return (string) $label;
    }