public <T> ObservableTransformer<? super T, T> transform(Observer<? super T> observer) {
    return group.transform(observer);
  }
public <T> ObservableTransformer<? super T, T> transform(Observer<? super T> observer) {
    return group.transform(observer);
  }
public < T > ObservableTransformer < ? super T , T > transform ( Observer < ? super T > observer ) { return group . transform ( observer ) ; }
Calls {@link ObservableGroup#transform(Observer)}  for the group managed by
this instance.
Calls {