func Must(op Op, err error) Op {
	if err != nil {
		panic(fmt.Errorf("unable to parse selector; %v", err.Error()))
	}

	return op
}
func Must(op Op, err error) Op {
	if err != nil {
		panic(fmt.Errorf("unable to parse selector; %v", err.Error()))
	}

	return op
}
func Must ( op Op , err error ) Op { if err != nil { panic ( fmt . Errorf ( " " , err . Error ( ) ) ) } return op }
// Must is a convenience method similar to template.Must
Must is a convenience method similar to template . Must