code: func decodeUint16(b []byte) (uint16, error) {
  	// Check the length of the slice of bytes.
  	if len(b) != 2 {
  		return 0, ErrInvalidByteLen
  	}
  
  	return uint16(b[0])<<8 | uint16(b[1]), nil
  }
docs: // decodeUint16 converts the slice of bytes in big-endian order
  // into an unsigned 16-bit integer.