code: func (f *Fpdf) UnicodeTranslatorFromDescriptor(cpStr string) (rep func(string) string) {
  	var str string
  	var ok bool
  	if f.err == nil {
  		if len(cpStr) == 0 {
  			cpStr = "cp1252"
  		}
  		str, ok = embeddedMapList[cpStr]
  		if ok {
  			rep, f.err = UnicodeTranslator(strings.NewReader(str))
  		} else {
  			rep, f.err = UnicodeTranslatorFromFile(filepath.Join(f.fontpath, cpStr) + ".map")
  		}
  	} else {
  		rep = doNothing
  	}
  	return
  }
docs: // UnicodeTranslatorFromDescriptor returns a function that can be used to
  // translate, where possible, utf-8 strings to a form that is compatible with
  // the specified code page. See UnicodeTranslator for more details.
  //
  // cpStr identifies a code page. A descriptor file in the font directory, set
  // with the fontDirStr argument in the call to New(), should have this name
  // plus the extension ".map". If cpStr is empty, it will be replaced with
  // "cp1252", the gofpdf code page default.
  //
  // If an error occurs reading the descriptor, the returned function is valid
  // but does not perform any rune translation.
  //
  // The CellFormat_codepage example demonstrates this method.