/**
  * @param string $username
  * @return Status
  */
 function fetchUser($username)
 {
     if ($username[0] == '#') {
         $id = intval(substr($username, 1));
         $user = CentralAuthGroupMembershipProxy::newFromId($id);
         if (!$user) {
             return Status::newFatal('noname', $id);
         }
     } else {
         $user = CentralAuthGroupMembershipProxy::newFromName($username);
         if (!$user) {
             return Status::newFatal('nosuchusershort', $username);
         }
     }
     return Status::newGood($user);
 }