code: func OptionParentUpdate(cid string, name, ip string) SandboxOption {
  	return func(sb *sandbox) {
  		sb.config.parentUpdates = append(sb.config.parentUpdates, parentUpdate{cid: cid, name: name, ip: ip})
  	}
  }
docs: // OptionParentUpdate function returns an option setter for parent container
  // which needs to update the IP address for the linked container.