This ID only equals amongst :class:`Story` instances which have the same owner and the same set of
        :class:`StoryItem`. For all other :class:`Story` instances this ID is different.

def unique_id(self) -> str:
        """
        This ID only equals amongst :class:`Story` instances which have the same owner and the same set of
        :class:`StoryItem`. For all other :class:`Story` instances this ID is different.
        """
        if not self._unique_id:
            id_list = [item.mediaid for item in self.get_items()]
            id_list.sort()
            self._unique_id = str().join([str(self.owner_id)] + list(map(str, id_list)))
        return self._unique_id