code: func (c *Chain) LastNode() Node {
  	if c.IsEmpty() {
  		return Node{}
  	}
  	group := c.nodeGroups[len(c.nodeGroups)-1]
  	return group.GetNode(0)
  }
docs: // LastNode returns the last node of the node list.
  // If the chain is empty, an empty node will be returned.
  // If the last node is a node group, the first node in the group will be returned.