code: func (t *UDPv4) Resolve(n *enode.Node) *enode.Node {
  	// If the node is present in the local table, no
  	// network interaction is required.
  	if intab := t.tab.Resolve(n); intab != nil {
  		return intab
  	}
  	// Otherwise, do a network lookup.
  	hash := n.ID()
  	result := t.LookupPubkey(n.Pubkey())
  	for _, n := range result {
  		if n.ID() == hash {
  			return n
  		}
  	}
  	return nil
  }
docs: // Resolve searches for a specific node with the given ID.
  // It returns nil if the node could not be found.