code: func SetupUserCreds(tc *client.TeleportClient, proxyHost string, creds UserCreds) error {
  	_, err := tc.AddKey(proxyHost, &creds.Key)
  	if err != nil {
  		return trace.Wrap(err)
  	}
  	err = tc.AddTrustedCA(creds.HostCA)
  	if err != nil {
  		return trace.Wrap(err)
  	}
  	return nil
  }
docs: // SetupUserCreds sets up user credentials for client