public function createFolder(Folder $parent = NULL, $name = "", $site_name = "")
 {
     if (trim($name) == "") {
         throw new e\CreationErrorException(S_SPAN . c\M::EMPTY_FOLDER_NAME . E_SPAN);
     }
     if ($parent == NULL && trim($site_name) == "") {
         throw new e\CreationErrorException(S_SPAN . c\M::EMPTY_SITE_NAME . E_SPAN);
     }
     $asset = AssetTemplate::getFolder();
     $asset->folder->name = $name;
     if (isset($parent)) {
         $asset->folder->parentFolderPath = $parent->getPath();
         $site_name = $parent->getSiteName();
     }
     $asset->folder->siteName = $site_name;
     return $this->createAsset($asset, Folder::TYPE, $this->getPath($parent, $name), $site_name);
 }