code: func (c *Client) GetVersion() (string, error) {
  	var clusterVersion string
  
  	versions, err := c.GetClusterVersions()
  	if err != nil {
  		return "", err
  	}
  	for _, v := range versions {
  		if clusterVersion != "" && clusterVersion != v {
  			return "", errors.Errorf("etcd cluster contains endpoints with mismatched versions: %v", versions)
  		}
  		clusterVersion = v
  	}
  	if clusterVersion == "" {
  		return "", errors.New("could not determine cluster etcd version")
  	}
  	return clusterVersion, nil
  }
docs: // GetVersion returns the etcd version of the cluster.
  // An error is returned if the version of all endpoints do not match