code: func (c *Chain) Nodes() (nodes []Node) {
  	for _, group := range c.nodeGroups {
  		if ns := group.Nodes(); len(ns) > 0 {
  			nodes = append(nodes, ns[0])
  		}
  	}
  	return
  }
docs: // Nodes returns the proxy nodes that the chain holds.
  // The first node in each group will be returned.