private function buildCenterReachableScopes(array $centers, ExportElementInterface $element) {
        $r = array();
        
        foreach($centers as $center) {
            $r[] = array(
                'center' => $center,
                'circles' => $this->authorizationHelper->getReachableScopes($this->user, 
                        $element->requiredRole(), $center)
            );
        }
        
        return $r;
    }