code: func (s *ReadState) GetStorage(address crypto.Address, key binary.Word256) (binary.Word256, error) {
  	keyFormat := keys.Storage.Fix(address)
  	tree, err := s.Forest.Reader(keyFormat.Prefix())
  	if err != nil {
  		return binary.Zero256, err
  	}
  	return binary.LeftPadWord256(tree.Get(keyFormat.KeyNoPrefix(key))), nil
  }
docs: // Storage