code: func normalizeBytes(number *builder.Builder) *builder.Builder {
  	normalizedNumber := normalize(number.String())
  	b := number.Bytes()
  	copy(b[0:len(normalizedNumber)], []byte(normalizedNumber))
  	return builder.NewBuilder(b)
  }
docs: // Normalizes a string of characters representing a phone number. This is
  // a wrapper for normalize(String number) but does in-place normalization
  // of the StringBuilder provided.