private function getDiskStatsForUser(User $user, $group_id)
 {
     $disk_stats = array('services' => array(), 'total' => $this->disk_usage_manager->returnTotalProjectSize($group_id), 'quota' => $this->getAllowedQuotaInBytes($group_id));
     if ($this->userHasAdminPrivileges($user, $group_id)) {
         $disk_stats['services'] = $this->disk_usage_manager->returnTotalServiceSizeByProject($group_id);
     }
     return $disk_stats;
 }