code: func RegisterCodabar(pdf barcodePdf, code string) string {
  	bcode, err := codabar.Encode(code)
  	return registerBarcode(pdf, bcode, err)
  }
docs: // RegisterCodabar registers a barcode of type Codabar to the PDF, but not to
  // the page. Use Barcode() with the return value to put the barcode on the page.