Thanks for the clarification.

Just for the record:

I have implemented __setstate__() such that it completely restores the state from just the inherited list state. That makes it independent of whether __init__() or __new__() is called:

    def __getstate__(self):
        state = self.__dict__.copy()
        del state['_lc_list']
        return state

    def __setstate__(self, state):
        self.__dict__.update(state)
        self._lc_list = _lc_list(self)

This issue can be closed.