code: func newChange(c merkletrie.Change) (*Change, error) {
  	ret := &Change{}
  
  	var err error
  	if ret.From, err = newChangeEntry(c.From); err != nil {
  		return nil, fmt.Errorf("From field: %s", err)
  	}
  
  	if ret.To, err = newChangeEntry(c.To); err != nil {
  		return nil, fmt.Errorf("To field: %s", err)
  	}
  
  	return ret, nil
  }
docs: // The following functions transform changes types form the merkletrie
  // package to changes types from this package.