$ret = GalleryEmbed::init(array('fullInit' => 'true'));
list($ret, $albumIds) = GalleryCoreApi::fetchAllItemIds('GalleryAlbumItem');
list($ret, $albums) = GalleryCoreApi::loadEntitiesById($albumIds);
foreach ($albums as $album) {
  $album->setTheme(null);
  $album->save();
}
$ret = GalleryCoreApi::setPluginParameter('module', 'core', 'default.theme', $g2Theme);
$ret = GalleryEmbed::done();