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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 modifyPdpContextRequest():
 """MODIFY PDP CONTEXT REQUEST Section 9.5.6"""

    a = TpPd(pd=0x8)
    b = MessageType(mesType=0x48)  # 01001000
    c = RadioPriorityAndSpareHalfOctets()
    d = LlcServiceAccessPointIdentifier()
    e = QualityOfService()
    packet = a / b / c / d / e
    return packet