code: func IsTrytesOfExactLength(trytes Trytes, length int) bool {
  	if len(trytes) != length {
  		return false
  	}
  	match, _ := regexp.MatchString("^[9A-Z]+$", string(trytes))
  	return match
  }
docs: // IsTrytesOfExactLength checks if input is correct trytes consisting of [9A-Z] and given length