code: func EtcdSupportedVersion(versionString string) (*version.Version, error) {
  	kubernetesVersion, err := version.ParseSemantic(versionString)
  	if err != nil {
  		return nil, err
  	}
  
  	if etcdStringVersion, ok := SupportedEtcdVersion[uint8(kubernetesVersion.Minor())]; ok {
  		etcdVersion, err := version.ParseSemantic(etcdStringVersion)
  		if err != nil {
  			return nil, err
  		}
  		return etcdVersion, nil
  	}
  	return nil, errors.Errorf("Unsupported or unknown Kubernetes version(%v)", kubernetesVersion)
  }
docs: // EtcdSupportedVersion returns officially supported version of etcd for a specific Kubernetes release
  // if passed version is not listed, the function returns nil and an error