Loads a memory object from memory.

        :param page_idx: the index into the page
        :returns: a tuple of the object

def load_mo(self, state, page_idx):
        """
        Loads a memory object from memory.

        :param page_idx: the index into the page
        :returns: a tuple of the object
        """
        mo = self._storage[page_idx-self._page_addr]
        return self._sinkhole if mo is None else mo