'Create and return a brand new L{MemoryIOSystem}.
The L{MemoryIOSystem} knows how to open new tunnel devices.
@return: The newly created I/O system object.
@rtype: L{MemoryIOSystem}'

def createSystem(self):

    system = MemoryIOSystem()
    system.registerSpecialDevice(Tunnel._DEVICE_NAME, Tunnel)
    return system
