code: func GetDNSVersion(dnsType kubeadmapi.DNSAddOnType) string {
  	switch dnsType {
  	case kubeadmapi.KubeDNS:
  		return KubeDNSVersion
  	default:
  		return CoreDNSVersion
  	}
  }
docs: // GetDNSVersion is a handy function that returns the DNS version by DNS type