code: func MarshalCertificatePEM(cert *x509.Certificate) ([]byte, error) {
  	var buf bytes.Buffer
  
  	err := pem.Encode(&buf, &pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw})
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  
  	return buf.Bytes(), nil
  }
docs: // MarshalCertificatePEM takes a *x509.Certificate and returns the PEM
  // encoded bytes.