code: func (s *handler) AttachTag(ref vim.ManagedObjectReference, tag vim.VslmTagEntry) vim.BaseMethodFault {
  	t := s.findTag(tag)
  	if t == nil {
  		return new(vim.NotFound)
  	}
  	s.Association[t.ID][internal.AssociatedObject(ref)] = true
  	return nil
  }
docs: // AttachTag is meant for internal use via simulator.Registry.tagManager