code: func (rca *RootCA) ParseValidateAndSignCSR(csrBytes []byte, cn, ou, org string) ([]byte, error) {
  	signRequest := PrepareCSR(csrBytes, cn, ou, org)
  	signer, err := rca.Signer()
  	if err != nil {
  		return nil, err
  	}
  	cert, err := signer.Sign(signRequest)
  	if err != nil {
  		return nil, errors.Wrap(err, "failed to sign node certificate")
  	}
  
  	return append(cert, rca.Intermediates...), nil
  }
docs: // ParseValidateAndSignCSR returns a signed certificate from a particular rootCA and a CSR.