code: def ias53(msg):
      
      d = hex2bin(data(msg))
  
      if d[12] == '0':
          return None
  
      ias = bin2int(d[13:23])    # knots
      return ias
docs: Indicated airspeed, DBS 5,3 message
  
      Args:
          msg (String): 28 bytes hexadecimal message
  
      Returns:
          int: indicated arispeed in knots