def stop_evaluator(self):
        """
        Stop the deferred feedback evaluation thread.
        """

        if self._evaluator_proc is None:
            raise RuntimeError("Evaluator not running this process.")

        if isinstance(self._evaluator_proc, Process):
            self._evaluator_proc.terminate()

        elif isinstance(self._evaluator_proc, Thread):
            self._evaluator_stop.set()
            self._evaluator_proc.join()
            self._evaluator_stop = None

        self._evaluator_proc = None

        Stop the deferred feedback evaluation thread.
        
src/core/trulens/core/session.py