code: func NodeToSelectableFields(node *api.Node) fields.Set {
  	objectMetaFieldsSet := generic.ObjectMetaFieldsSet(&node.ObjectMeta, false)
  	specificFieldsSet := fields.Set{
  		"spec.unschedulable": fmt.Sprint(node.Spec.Unschedulable),
  	}
  	return generic.MergeFieldsSets(objectMetaFieldsSet, specificFieldsSet)
  }
docs: // NodeToSelectableFields returns a field set that represents the object.