code: func ParseCertificatePEM(bytes []byte) (*x509.Certificate, error) {
  	block, _ := pem.Decode(bytes)
  	if block == nil {
  		return nil, trace.BadParameter("expected PEM-encoded block")
  	}
  	cert, err := x509.ParseCertificate(block.Bytes)
  	if err != nil {
  		return nil, trace.BadParameter(err.Error())
  	}
  	return cert, nil
  }
docs: // ParseCertificatePEM parses PEM-encoded certificate