code: func GenerateSelfSignedCA(entity pkix.Name, dnsNames []string, ttl time.Duration) ([]byte, []byte, error) {
  	priv, err := rsa.GenerateKey(rand.Reader, teleport.RSAKeySize)
  	if err != nil {
  		return nil, nil, trace.Wrap(err)
  	}
  	return GenerateSelfSignedCAWithPrivateKey(priv, entity, dnsNames, ttl)
  }
docs: // GenerateSelfSignedCA generates self-signed certificate authority used for internal inter-node communications