code: func (v *validator) ValidateLabels(labels map[types.ACIdentifier]string) error {
  	for n, rv := range labels {
  		if av, ok := v.manifest.GetLabel(n.String()); ok {
  			if rv != av {
  				return fmt.Errorf("requested value for label %q: %q differs from fetched aci label value: %q", n, rv, av)
  			}
  		} else {
  			return fmt.Errorf("requested label %q not provided by the image manifest", n)
  		}
  	}
  	return nil
  }
docs: // ValidateLabels checks if desired image labels are actually the same as
  // the ones in the image manifest.