code: func readCertValidity(kr KeyReader) (time.Time, time.Time, error) {
  	var zeroTime time.Time
  	// Read the Cert
  	cert, _, err := kr.Read()
  	if err != nil {
  		return zeroTime, zeroTime, err
  	}
  
  	// Create an x509 certificate out of the contents on disk
  	certBlock, _ := pem.Decode(cert)
  	if certBlock == nil {
  		return zeroTime, zeroTime, errors.New("failed to decode certificate block")
  	}
  	X509Cert, err := x509.ParseCertificate(certBlock.Bytes)
  	if err != nil {
  		return zeroTime, zeroTime, err
  	}
  
  	return X509Cert.NotBefore, X509Cert.NotAfter, nil
  
  }
docs: // readCertValidity returns the certificate issue and expiration time