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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def cmServiceRequest(PriorityLevel_presence=0):
 """CM SERVICE REQUEST Section 9.2.9"""

    a = TpPd(pd=0x5)
    b = MessageType(mesType=0x24)  # 00100100
    c = CmServiceTypeAndCiphKeySeqNr()
    e = MobileStationClassmark2()
    f = MobileId()
    packet = a / b / c / e / f
    if PriorityLevel_presence is 1:
        g = PriorityLevelHdr(ieiPL=0x8, eightBitPL=0x0)
        packet = packet / g
    return packet