code: def passcode(callsign):
      
      assert isinstance(callsign, str)
  
      callsign = callsign.split('-')[0].upper()
  
      code = 0x73e2
      for i, char in enumerate(callsign):
          code ^= ord(char) << (8 if not i % 2 else 0)
  
      return code & 0x7fff
docs: Takes a CALLSIGN and returns passcode