code: def is40(msg):
      
  
      if allzeros(msg):
          return False
  
      d = hex2bin(data(msg))
  
      # status bit 1, 14, and 27
  
      if wrongstatus(d, 1, 2, 13):
          return False
  
      if wrongstatus(d, 14, 15, 26):
          return False
  
      if wrongstatus(d, 27, 28, 39):
          return False
  
      if wrongstatus(d, 48, 49, 51):
          return False
  
      if wrongstatus(d, 54, 55, 56):
          return False
  
      # bits 40-47 and 52-53 shall all be zero
  
      if bin2int(d[39:47]) != 0:
          return False
  
      if bin2int(d[51:53]) != 0:
          return False
  
      return True
docs: Check if a message is likely to be BDS code 4,0
  
      Args:
          msg (String): 28 bytes hexadecimal message string
  
      Returns:
          bool: True or False