private E findhelp(BPNode<Key,E> rt, Key k) {
  int currec = binaryle(rt.keys(), rt.numrecs(), k);
  if (rt.isLeaf()) {
    if ((((BPLeaf<Key,E>)rt).keys())[currec] == k) {
      return ((BPLeaf<Key,E>)rt).recs(currec);
    }
    else { return null; }
  }
  else{
    return findhelp(((BPInternal<Key,E>)rt).pointers(currec), k);
  }
}
