def warning(self):
        """Issue warning that this singleton already exists."""

        name = SingletonPerName._id_to_name_map[id(self)]
        k = self.__class__.__name__, name
        if k in SingletonPerName._instances:
            SingletonPerName._instances[k].warning()
        else:
            raise RuntimeError(
                f"Instance of singleton type/name {k} does not exist."
            )
Issue warning that this singleton already exists.
src/trulens_eval/trulens_eval/utils/python.py