code: func (b *Bundle) MustTfunc(pref string, prefs ...string) TranslateFunc {
  	tfunc, err := b.Tfunc(pref, prefs...)
  	if err != nil {
  		panic(err)
  	}
  	return tfunc
  }
docs: // MustTfunc is similar to Tfunc except it panics if an error happens.