/**
* @param SS_HTTPResponse $r
* @return SS_HTTPResponse|void
* @throws SS_HTTPResponse_Exception
*/
public function handleGroupUnselect(SS_HTTPResponse $r)
{
if (!Member::currentUser()) {
return $this->httpError(403);
}
$this->presentation->removeFromGroupList();
return new SS_HTTPResponse("Presentation unselected.", 200);
}