in aidial_sdk/chat_completion/choice.py [0:0]
def create_stage(self, name: Optional[str] = None) -> Stage:
if not self._opened:
raise runtime_error("Trying to create stage to an unopened choice")
if self._closed:
raise runtime_error("Trying to create stage to a closed choice")
stage = Stage(self._queue, self._index, self._last_stage_index, name)
self._last_stage_index += 1
return stage