code: func getSANs(cert *x509.Certificate) []string {
  	var sans []string
  	if cert == nil {
  		return sans
  	}
  
  	sans = append(sans, cert.DNSNames...)
  	sans = append(sans, cert.EmailAddresses...)
  
  	var ips []string
  	for _, ip := range cert.IPAddresses {
  		ips = append(ips, ip.String())
  	}
  	sans = append(sans, ips...)
  
  	var uris []string
  	for _, uri := range cert.URIs {
  		uris = append(uris, uri.String())
  	}
  
  	return append(sans, uris...)
  }
docs: // getSANs get the Subject Alternate Name values.