code: func namespace() string {
  	if ns := os.Getenv("TILLER_NAMESPACE"); ns != "" {
  		return ns
  	}
  
  	// Fall back to the namespace associated with the service account token, if available
  	if data, err := ioutil.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace"); err == nil {
  		if ns := strings.TrimSpace(string(data)); len(ns) > 0 {
  			return ns
  		}
  	}
  
  	return environment.DefaultTillerNamespace
  }
docs: // namespace returns the namespace of tiller