code: func BytesToTrytes(bytes []byte, numTrytes ...int) (Trytes, error) {
  	numTrits := []int{}
  	if len(numTrytes) > 0 {
  		numTrits = append(numTrits, numTrytes[0]*3)
  	}
  
  	trits, err := BytesToTrits(bytes, numTrits...)
  	if err != nil {
  		return "", err
  	}
  
  	trits = PadTrits(trits, int(nearestGreaterMultipleOfThree(uint64(len(trits)))))
  	return TritsToTrytes(trits)
  }
docs: // BytesToTrytes converts bytes to Trytes. Returns an error if the bytes slice is not 48 in length.