code: func (c *ClusterNameV2) CheckAndSetDefaults() error {
  	// make sure we have defaults for all metadata fields
  	err := c.Metadata.CheckAndSetDefaults()
  	if err != nil {
  		return trace.Wrap(err)
  	}
  
  	if c.Spec.ClusterName == "" {
  		return trace.BadParameter("cluster name is required")
  	}
  
  	return nil
  }
docs: // CheckAndSetDefaults checks validity of all parameters and sets defaults.