pkg/relabel/relabel.go
func MustNewRegexp(s string) Regexp {
	re, err := NewRegexp(s)
	if err != nil {
		panic(err)
	}
	return re
}
func MustNewRegexp(s string) Regexp {
	re, err := NewRegexp(s)
	if err != nil {
		panic(err)
	}
	return re
}
// MustNewRegexp works like NewRegexp, but panics if the regular expression does not compile.