code: func asciiToInt(bts []byte) (ret int, err error) {
  	// ASCII numbers all start with the high-order bits 0011.
  	// If you see that, and the next bits are 0-9 (0000 - 1001) you can grab those
  	// bits and interpret them directly as an integer.
  	var n int
  	if n = len(bts); n < 1 {
  		return 0, fmt.Errorf("converting empty bytes to int")
  	}
  	for i := 0; i < n; i++ {
  		if bts[i]&0xf0 != 0x30 {
  			return 0, fmt.Errorf("%s is not a numeric character", string(bts[i]))
  		}
  		ret += int(bts[i]&0xf) * pow(10, n-i-1)
  	}
  	return ret, nil
  }
docs: // asciiToInt converts bytes to int.