protected function updateExtensions(Package &$model, KeekoPackageSchema $pkg)
 {
     // remove all existing extensions from this package first
     ExtensionQuery::create()->filterByPackage($model)->delete();
     // add them one by one
     foreach ($pkg->getAllExtensions() as $key => $exts) {
         foreach ($exts as $data) {
             $ext = new Extension();
             $ext->setKey($key);
             $ext->setData(Json::encode($data, Json::UNESCAPED_SLASHES));
             $ext->setPackage($model);
             $ext->save();
         }
     }
 }