func Caller() string {
	_, file, line, ok := runtime.Caller(2)
	if !ok {
		return "?"
	}

	rel, err := filepath.Rel(RootPath(), file)
	if err != nil {
		return "?"
	}

	return fmt.Sprintf("%s:%d", rel, line)
}
func Caller() string {
	_, file, line, ok := runtime.Caller(2)
	if !ok {
		return "?"
	}

	rel, err := filepath.Rel(RootPath(), file)
	if err != nil {
		return "?"
	}

	return fmt.Sprintf("%s:%d", rel, line)
}
// Caller returns a caller's call location. If F1 calls F2 which in its turn
// calls Caller, then this function will return a location within F1 where it
// calls F2.