code: def routingAreaUpdateRequest(PTmsiSignature_presence=0,
                               GprsTimer_presence=0,
                               DrxParameter_presence=0,
                               TmsiStatus_presence=0):
      
      a = TpPd(pd=0x3)
      b = MessageType(mesType=0x8)  # 00001000
      c = UpdateTypeAndCiphKeySeqNr()
      e = RoutingAreaIdentification()
      f = MsNetworkCapability()
      packet = a / b / c / e / f
      if PTmsiSignature_presence is 1:
          g = PTmsiSignature(ieiPTS=0x19)
          packet = packet / g
      if GprsTimer_presence is 1:
          h = GprsTimer(ieiGT=0x17)
          packet = packet / h
      if DrxParameter_presence is 1:
          i = DrxParameter(ieiDP=0x27)
          packet = packet / i
      if TmsiStatus_presence is 1:
          j = TmsiStatus(ieiTS=0x9)
          packet = packet / j
      return packet
docs: ROUTING AREA UPDATE REQUEST Section 9.4.14