code: func GetVersion(client *tuf.Client, name string) (string, error) {
  	targets, err := client.Targets()
  	if err != nil {
  		return "", err
  	}
  	target, ok := targets[name]
  	if !ok {
  		return "", fmt.Errorf("missing %q in tuf targets", name)
  	}
  	if target.Custom == nil || len(*target.Custom) == 0 {
  		return "", errors.New("missing custom metadata in tuf target")
  	}
  	var data struct {
  		Version string
  	}
  	json.Unmarshal(*target.Custom, &data)
  	if data.Version == "" {
  		return "", errors.New("missing version in tuf target")
  	}
  	return data.Version, nil
  }
docs: // GetVersion returns the given target's version from custom metadata