code: func (u *ResourceCommand) createCertAuthority(client auth.ClientI, raw services.UnknownResource) error {
  	certAuthority, err := services.GetCertAuthorityMarshaler().UnmarshalCertAuthority(raw.Raw)
  	if err != nil {
  		return trace.Wrap(err)
  	}
  	if err := client.UpsertCertAuthority(certAuthority); err != nil {
  		return trace.Wrap(err)
  	}
  	fmt.Printf("certificate authority '%s' has been updated\n", certAuthority.GetName())
  	return nil
  }
docs: // createCertAuthority creates certificate authority