code: func (n *cachedNode) obj(hash common.Hash) node {
  	if node, ok := n.node.(rawNode); ok {
  		return mustDecodeNode(hash[:], node)
  	}
  	return expandNode(hash[:], n.node)
  }
docs: // obj returns the decoded and expanded trie node, either directly from the cache,
  // or by regenerating it from the rlp encoded blob.