code: def systemInformationType4(ChannelDescription_presence=0,
                             MobileAllocation_presence=0):
      
      a = L2PseudoLength()
      b = TpPd(pd=0x6)
      c = MessageType(mesType=0x1C)  # 000111100
      d = LocalAreaId()
      e = CellSelectionParameters()
      f = RachControlParameters()
      packet = a / b / c / d / e / f
      if ChannelDescription_presence is 1:
          g = ChannelDescriptionHdr(ieiCD=0x64, eightBitCD=0x0)
          packet = packet / g
      if MobileAllocation_presence is 1:
          h = MobileAllocationHdr(ieiMA=0x72, eightBitMA=0x0)
          packet = packet / h
      i = Si4RestOctets()
      packet = packet / i
      return packet
docs: SYSTEM INFORMATION TYPE 4 Section 9.1.36