code: func (iter *EncodedObjectLookupIter) Next() (plumbing.EncodedObject, error) {
  	if iter.pos >= len(iter.series) {
  		return nil, io.EOF
  	}
  
  	hash := iter.series[iter.pos]
  	obj, err := iter.storage.EncodedObject(iter.t, hash)
  	if err == nil {
  		iter.pos++
  	}
  
  	return obj, err
  }
docs: // Next returns the next object from the iterator. If the iterator has reached
  // the end it will return io.EOF as an error. If the object can't be found in
  // the object storage, it will return plumbing.ErrObjectNotFound as an error.
  // If the object is retreieved successfully error will be nil.