code: def gs50(msg):
      
      d = hex2bin(data(msg))
  
      if d[23] == '0':
          return None
  
      spd = bin2int(d[24:34]) * 2    # kts
      return spd
docs: Ground speed, BDS 5,0 message
  
      Args:
          msg (String): 28 bytes hexadecimal message (BDS50) string
  
      Returns:
          int: ground speed in knots