code: func CheckArmor62(hdr string, ftr string, typ MessageType) (brand string, err error) {
  	brand, err = parseFrame(hdr, typ, headerMarker)
  	if err != nil {
  		return "", err
  	}
  	var b2 string
  	b2, err = parseFrame(ftr, typ, footerMarker)
  	if err != nil {
  		return "", err
  	}
  
  	if b2 != brand {
  		return "", makeErrBadFrame("brand mismatch: %q != %q", brand, b2)
  	}
  	return brand, nil
  }
docs: // CheckArmor62 checks that the frame matches our standard
  // begin/end frame