code: func Load(p Persister, id []byte, comparator Comparator) (ReadableTree, error) {
  	items, err := p.Load(id)
  	if err != nil {
  		return nil, err
  	}
  
  	if len(items) == 0 || items[0] == nil {
  		return nil, ErrTreeNotFound
  	}
  
  	rt, err := treeFromBytes(p, items[0].Payload, comparator)
  	if err != nil {
  		return nil, err
  	}
  
  	return rt, nil
  }
docs: // Load returns a ReadableTree from persistence.  The provided
  // config should contain a persister that can be used for this purpose.
  // An error is returned if the tree could not be found or an error
  // occurred in the persistence layer.