code: func (u *UIDTrackingControllerExpectations) GetUIDs(controllerKey string) sets.String {
  	if uid, exists, err := u.uidStore.GetByKey(controllerKey); err == nil && exists {
  		return uid.(*UIDSet).String
  	}
  	return nil
  }
docs: // GetUIDs is a convenience method to avoid exposing the set of expected uids.
  // The returned set is not thread safe, all modifications must be made holding
  // the uidStoreLock.