import asyncio
import logging
import re
from inspect import iscoroutinefunction
from typing import Any, Awaitable, Callable, Dict, List, Mapping, Optional, Sequence, Union, cast
from autogen_core import AgentRuntime, CancellationToken, Component, ComponentModel
from autogen_core.model_context import (
ChatCompletionContext,
UnboundedChatCompletionContext,
)
from autogen_core.models import (
AssistantMessage,
ChatCompletionClient,
CreateResult,
LLMMessage,
ModelFamily,
SystemMessage,
UserMessage,
)
from pydantic import BaseModel
from typing_extensions import Self
from ... import TRACE_LOGGER_NAME
from ...agents import BaseChatAgent
from ...base import ChatAgent, TerminationCondition
from ...messages import (
BaseAgentEvent,
BaseChatMessage,
HandoffMessage,
MessageFactory,
ModelClientStreamingChunkEvent,
SelectorEvent,
)
from ...state import SelectorManagerState
from ._base_group_chat import BaseGroupChat
from ._base_group_chat_manager import BaseGroupChatManager
from ._events import GroupChatTermination
trace_logger = logging.getLogger(TRACE_LOGGER_NAME)
SyncSelectorFunc = Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], str | None]
AsyncSelectorFunc = Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], Awaitable[str | None]]
SelectorFuncType = Union[SyncSelectorFunc | AsyncSelectorFunc]
SyncCandidateFunc = Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], List[str]]
AsyncCandidateFunc = Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], Awaitable[List[str]]]
CandidateFuncType = Union[SyncCandidateFunc | AsyncCandidateFunc]
class SelectorGroupChatManager(BaseGroupChatManager):
"""一个使用 ChatCompletion 模型和自定义选择函数来选择下一位发言者的群聊管理器。"""
def __init__(
self,
name: str,
group_topic_type: str,
output_topic_type: str,
participant_topic_types: List[str],
participant_names: List[str],
participant_descriptions: List[str],
output_message_queue: asyncio.Queue[BaseAgentEvent | BaseChatMessage | GroupChatTermination],
termination_condition: TerminationCondition | None,
max_turns: int | None,
message_factory: MessageFactory,
model_client: ChatCompletionClient,
selector_prompt: str,
allow_repeated_speaker: bool,
selector_func: Optional[SelectorFuncType],
max_selector_attempts: int,
candidate_func: Optional[CandidateFuncType],
emit_team_events: bool,
model_context: ChatCompletionContext | None,
model_client_streaming: bool = False,
) -> None:
super().__init__(
name,
group_topic_type,
output_topic_type,
participant_topic_types,
participant_names,
participant_descriptions,
output_message_queue,
termination_condition,
max_turns,
message_factory,
emit_team_events,
)
self._model_client = model_client
self._selector_prompt = selector_prompt
self._previous_speaker: str | None = None
self._allow_repeated_speaker = allow_repeated_speaker
self._selector_func = selector_func
self._is_selector_func_async = iscoroutinefunction(self._selector_func)
self._max_selector_attempts = max_selector_attempts
self._candidate_func = candidate_func
self._is_candidate_func_async = iscoroutinefunction(self._candidate_func)
self._model_client_streaming = model_client_streaming
if model_context is not None:
self._model_context = model_context
else:
self._model_context = UnboundedChatCompletionContext()
self._cancellation_token = CancellationToken()
async def validate_group_state(self, messages: List[BaseChatMessage] | None) -> None:
pass
async def reset(self) -> None:
self._current_turn = 0
self._message_thread.clear()
await self._model_context.clear()
if self._termination_condition is not None:
await self._termination_condition.reset()
self._previous_speaker = None
async def save_state(self) -> Mapping[str, Any]:
state = SelectorManagerState(
message_thread=[msg.dump() for msg in self._message_thread],
current_turn=self._current_turn,
previous_speaker=self._previous_speaker,
)
return state.model_dump()
async def load_state(self, state: Mapping[str, Any]) -> None:
selector_state = SelectorManagerState.model_validate(state)
self._message_thread = [self._message_factory.create(msg) for msg in selector_state.message_thread]
await self._add_messages_to_context(
self._model_context, [msg for msg in self._message_thread if isinstance(msg, BaseChatMessage)]
)
self._current_turn = selector_state.current_turn
self._previous_speaker = selector_state.previous_speaker
@staticmethod
async def _add_messages_to_context(
model_context: ChatCompletionContext,
messages: Sequence[BaseChatMessage],
) -> None:
"""
将传入消息添加到模型上下文中。
"""
for msg in messages:
if isinstance(msg, HandoffMessage):
for llm_msg in msg.context:
await model_context.add_message(llm_msg)
await model_context.add_message(msg.to_model_message())
async def update_message_thread(self, messages: Sequence[BaseAgentEvent | BaseChatMessage]) -> None:
self._message_thread.extend(messages)
base_chat_messages = [m for m in messages if isinstance(m, BaseChatMessage)]
await self._add_messages_to_context(self._model_context, base_chat_messages)
async def select_speaker(self, thread: Sequence[BaseAgentEvent | BaseChatMessage]) -> List[str] | str:
"""使用 ChatCompletion 客户端选择群聊中的下一位发言者,
如果选择器函数返回发言者名称则优先使用该结果。
.. note::
该方法始终返回单个发言者名称。
关键假设是代理类型与主题类型相同,我们将其用作代理名称。
"""
# Use the selector function if provided.
if self._selector_func is not None:
if self._is_selector_func_async:
async_selector_func = cast(AsyncSelectorFunc, self._selector_func)
speaker = await async_selector_func(thread)
else:
sync_selector_func = cast(SyncSelectorFunc, self._selector_func)
speaker = sync_selector_func(thread)
if speaker is not None:
if speaker not in self._participant_names:
raise ValueError(
f"Selector function returned an invalid speaker name: {speaker}. "
f"Expected one of: {self._participant_names}."
)
# Skip the model based selection.
return [speaker]
# Use the candidate function to filter participants if provided
if self._candidate_func is not None:
if self._is_candidate_func_async:
async_candidate_func = cast(AsyncCandidateFunc, self._candidate_func)
participants = await async_candidate_func(thread)
else:
sync_candidate_func = cast(SyncCandidateFunc, self._candidate_func)
participants = sync_candidate_func(thread)
if not participants:
raise ValueError("Candidate function must return a non-empty list of participant names.")
if not all(p in self._participant_names for p in participants):
raise ValueError(
f"Candidate function returned invalid participant names: {participants}. "
f"Expected one of: {self._participant_names}."
)
else:
# Construct the candidate agent list to be selected from, skip the previous speaker if not allowed.
if self._previous_speaker is not None and not self._allow_repeated_speaker:
participants = [p for p in self._participant_names if p != self._previous_speaker]
else:
participants = list(self._participant_names)
assert len(participants) > 0
# Construct agent roles.
# Each agent sould appear on a single line.
roles = ""
for topic_type, description in zip(self._participant_names, self._participant_descriptions, strict=True):
roles += re.sub(r"\s+", " ", f"{topic_type}: {description}").strip() + "\n"
roles = roles.strip()
# Select the next speaker.
if len(participants) > 1:
agent_name = await self._select_speaker(roles, participants, self._max_selector_attempts)
else:
agent_name = participants[0]
self._previous_speaker = agent_name
trace_logger.debug(f"Selected speaker: {agent_name}")
return [agent_name]
def construct_message_history(self, message_history: List[LLMMessage]) -> str:
# Construct the history of the conversation.
history_messages: List[str] = []
for msg in message_history:
if isinstance(msg, UserMessage) or isinstance(msg, AssistantMessage):
message = f"{msg.source}: {msg.content}"
history_messages.append(
message.rstrip() + "\n\n"
) # Create some consistency for how messages are separated in the transcript
history: str = "\n".join(history_messages)
return history
async def _select_speaker(self, roles: str, participants: List[str], max_attempts: int) -> str:
model_context_messages = await self._model_context.get_messages()
model_context_history = self.construct_message_history(model_context_messages)
select_speaker_prompt = self._selector_prompt.format(
roles=roles, participants=str(participants), history=model_context_history
)
select_speaker_messages: List[SystemMessage | UserMessage | AssistantMessage]
if ModelFamily.is_openai(self._model_client.model_info["family"]):
select_speaker_messages = [SystemMessage(content=select_speaker_prompt)]
else:
# Many other models need a UserMessage to respond to
select_speaker_messages = [UserMessage(content=select_speaker_prompt, source="user")]
num_attempts = 0
while num_attempts < max_attempts:
num_attempts += 1
if self._model_client_streaming:
chunk: CreateResult | str = ""
async for _chunk in self._model_client.create_stream(messages=select_speaker_messages):
chunk = _chunk
if self._emit_team_events:
if isinstance(chunk, str):
await self._output_message_queue.put(
ModelClientStreamingChunkEvent(content=cast(str, _chunk), source=self._name)
)
else:
assert isinstance(chunk, CreateResult)
assert isinstance(chunk.content, str)
await self._output_message_queue.put(
SelectorEvent(content=chunk.content, source=self._name)
)
# The last chunk must be CreateResult.
assert isinstance(chunk, CreateResult)
response = chunk
else:
response = await self._model_client.create(messages=select_speaker_messages)
assert isinstance(response.content, str)
select_speaker_messages.append(AssistantMessage(content=response.content, source="selector"))
# NOTE: we use all participant names to check for mentions, even if the previous speaker is not allowed.
# This is because the model may still select the previous speaker, and we want to catch that.
mentions = self._mentioned_agents(response.content, self._participant_names)
if len(mentions) == 0:
trace_logger.debug(f"Model failed to select a valid name: {response.content} (attempt {num_attempts})")
feedback = f"No valid name was mentioned. Please select from: {str(participants)}."
select_speaker_messages.append(UserMessage(content=feedback, source="user"))
elif len(mentions) > 1:
trace_logger.debug(f"Model selected multiple names: {str(mentions)} (attempt {num_attempts})")
feedback = (
f"Expected exactly one name to be mentioned. Please select only one from: {str(participants)}."
)
select_speaker_messages.append(UserMessage(content=feedback, source="user"))
else:
agent_name = list(mentions.keys())[0]
if (
not self._allow_repeated_speaker
and self._previous_speaker is not None
and agent_name == self._previous_speaker
):
trace_logger.debug(f"Model selected the previous speaker: {agent_name} (attempt {num_attempts})")
feedback = (
f"Repeated speaker is not allowed, please select a different name from: {str(participants)}."
)
select_speaker_messages.append(UserMessage(content=feedback, source="user"))
else:
# Valid selection
trace_logger.debug(f"Model selected a valid name: {agent_name} (attempt {num_attempts})")
return agent_name
if self._previous_speaker is not None:
trace_logger.warning(f"Model failed to select a speaker after {max_attempts}, using the previous speaker.")
return self._previous_speaker
trace_logger.warning(
f"Model failed to select a speaker after {max_attempts} and there was no previous speaker, using the first participant."
)
return participants[0]
def _mentioned_agents(self, message_content: str, agent_names: List[str]) -> Dict[str, int]:
"""统计在提供的消息内容中每个代理被提及的次数。
代理名称在以下任一条件下匹配(均区分大小写):
- 精确名称匹配
- 若代理名称包含下划线,则匹配时将下划线替换为空格(例如 'Story_writer' == 'Story writer')
- 若代理名称包含下划线,则匹配时将下划线替换为 '\\_'(例如 'Story_writer' == 'Story\\_writer')
Args:
message_content (Union[str, List]): 消息内容,可以是单个字符串或字符串列表。
agents (List[Agent]): 代理对象列表,每个对象都有要在消息内容中搜索的 'name' 属性。
Returns:
Dict: 被提及代理的计数器。
"""
mentions: Dict[str, int] = dict()
for name in agent_names:
# Finds agent mentions, taking word boundaries into account,
# accommodates escaping underscores and underscores as spaces
regex = (
r"(?<=\W)("
+ re.escape(name)
+ r"|"
+ re.escape(name.replace("_", " "))
+ r"|"
+ re.escape(name.replace("_", r"\_"))
+ r")(?=\W)"
)
# Pad the message to help with matching
count = len(re.findall(regex, f" {message_content} "))
if count > 0:
mentions[name] = count
return mentions
class SelectorGroupChatConfig(BaseModel):
"""SelectorGroupChat 的声明式配置。"""
participants: List[ComponentModel]
model_client: ComponentModel
termination_condition: ComponentModel | None = None
max_turns: int | None = None
selector_prompt: str
allow_repeated_speaker: bool
# selector_func: ComponentModel | None
max_selector_attempts: int = 3
emit_team_events: bool = False
model_client_streaming: bool = False
model_context: ComponentModel | None = None
[文档]
class SelectorGroupChat(BaseGroupChat, Component[SelectorGroupChatConfig]):
"""一个拥有参与者的群聊团队,参与者轮流向所有人发布消息,
使用 ChatCompletion 模型在每条消息后选择下一位发言者。
Args:
participants (List[ChatAgent]): 群聊中的参与者,
必须具有唯一名称且至少两名参与者。
model_client (ChatCompletionClient): 用于选择下一位发言者的 ChatCompletion 模型客户端。
termination_condition (TerminationCondition, optional): 群聊的终止条件。默认为 None。
没有终止条件时,群聊将无限期运行。
max_turns (int, optional): 群聊停止前的最大轮数。默认为 None,表示无限制。
selector_prompt (str, optional): 用于选择下一位发言者的提示模板。
可用字段:'{roles}'、'{participants}' 和 '{history}'。
`{participants}` 是候选发言者名称列表,格式为 `["<name1>", "<name2>", ...]`。
`{roles}` 是候选代理名称和描述的新行分隔列表,每行格式为:`"<name> : <description>"`。
`{history}` 是格式化为双新行分隔的名称和消息内容的对话历史,每条消息格式为:`"<name> : <message content>"`。
allow_repeated_speaker (bool, optional): 是否将上一位发言者包含在下轮候选列表中。
默认为 False。模型仍可能选择上一位发言者——若发生此情况将记录警告。
max_selector_attempts (int, optional): 使用模型选择发言者的最大尝试次数。默认为 3。
若达到最大尝试次数后模型仍未能选择发言者,将使用上一位发言者(若可用),
否则使用第一位参与者。
selector_func (Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], str | None], Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], Awaitable[str | None]], optional): 自定义选择函数,
接收对话历史并返回下一位发言者名称。
若提供,此函数将覆盖模型选择逻辑。
若函数返回 None,则使用模型选择下一位发言者。
candidate_func (Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], List[str]], Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], Awaitable[List[str]]], optional):
自定义函数,接收对话历史并返回模型选择下位发言者的过滤候选列表。
若返回空列表或 `None`,`SelectorGroupChat` 将抛出 `ValueError`。
仅当未设置 `selector_func` 时使用此函数。若设置此函数,`allow_repeated_speaker` 将被忽略。
custom_message_types (List[type[BaseAgentEvent | BaseChatMessage]], optional): 群聊中使用的自定义消息类型列表。
若使用自定义消息类型或代理产生自定义消息类型,需在此指定。
确保自定义消息类型是 :class:`~autogen_agentchat.messages.BaseAgentEvent` 或 :class:`~autogen_agentchat.messages.BaseChatMessage` 的子类。
emit_team_events (bool, optional): 是否通过 :meth:`BaseGroupChat.run_stream` 发出团队事件。默认为 False。
model_client_streaming (bool, optional): 是否为模型客户端启用流式传输。(适用于 QwQ 等推理模型)。默认为 False。
model_context (ChatCompletionContext | None, optional): 存储和检索 :class:`~autogen_core.models.LLMMessage` 的模型上下文。
可预加载初始消息。模型上下文中的消息将用于发言者选择。团队重置时将清除初始消息。
Raises:
ValueError: 若参与者少于两名或选择提示无效时抛出。
Examples:
含多个参与者的团队:
.. code-block:: python
import asyncio
from autogen_ext.models.openai import OpenAIChatCompletionClient
from autogen_agentchat.agents import AssistantAgent
from autogen_agentchat.teams import SelectorGroupChat
from autogen_agentchat.conditions import TextMentionTermination
from autogen_agentchat.ui import Console
async def main() -> None:
model_client = OpenAIChatCompletionClient(model="gpt-4o")
async def lookup_hotel(location: str) -> str:
return f"Here are some hotels in {location}: hotel1, hotel2, hotel3."
async def lookup_flight(origin: str, destination: str) -> str:
return f"Here are some flights from {origin} to {destination}: flight1, flight2, flight3."
async def book_trip() -> str:
return "Your trip is booked!"
travel_advisor = AssistantAgent(
"Travel_Advisor",
model_client,
tools=[book_trip],
description="Helps with travel planning.",
)
hotel_agent = AssistantAgent(
"Hotel_Agent",
model_client,
tools=[lookup_hotel],
description="Helps with hotel booking.",
)
flight_agent = AssistantAgent(
"Flight_Agent",
model_client,
tools=[lookup_flight],
description="Helps with flight booking.",
)
termination = TextMentionTermination("TERMINATE")
team = SelectorGroupChat(
[travel_advisor, hotel_agent, flight_agent],
model_client=model_client,
termination_condition=termination,
)
await Console(team.run_stream(task="Book a 3-day trip to new york."))
asyncio.run(main())
含自定义选择函数的团队:
.. code-block:: python
import asyncio
from typing import Sequence
from autogen_ext.models.openai import OpenAIChatCompletionClient
from autogen_agentchat.agents import AssistantAgent
from autogen_agentchat.teams import SelectorGroupChat
from autogen_agentchat.conditions import TextMentionTermination
from autogen_agentchat.ui import Console
from autogen_agentchat.messages import BaseAgentEvent, BaseChatMessage
async def main() -> None:
model_client = OpenAIChatCompletionClient(model="gpt-4o")
def check_calculation(x: int, y: int, answer: int) -> str:
if x + y == answer:
return "Correct!"
else:
return "Incorrect!"
agent1 = AssistantAgent(
"Agent1",
model_client,
description="For calculation",
system_message="Calculate the sum of two numbers",
)
agent2 = AssistantAgent(
"Agent2",
model_client,
tools=[check_calculation],
description="For checking calculation",
system_message="Check the answer and respond with 'Correct!' or 'Incorrect!'",
)
def selector_func(messages: Sequence[BaseAgentEvent | BaseChatMessage]) -> str | None:
if len(messages) == 1 or messages[-1].to_text() == "Incorrect!":
return "Agent1"
if messages[-1].source == "Agent1":
return "Agent2"
return None
termination = TextMentionTermination("Correct!")
team = SelectorGroupChat(
[agent1, agent2],
model_client=model_client,
selector_func=selector_func,
termination_condition=termination,
)
await Console(team.run_stream(task="What is 1 + 1?"))
asyncio.run(main())
含自定义模型上下文的团队:
.. code-block:: python
import asyncio
from autogen_core.model_context import BufferedChatCompletionContext
from autogen_ext.models.openai import OpenAIChatCompletionClient
from autogen_agentchat.agents import AssistantAgent
from autogen_agentchat.conditions import TextMentionTermination
from autogen_agentchat.teams import SelectorGroupChat
from autogen_agentchat.ui import Console
async def main() -> None:
model_client = OpenAIChatCompletionClient(model="gpt-4o")
model_context = BufferedChatCompletionContext(buffer_size=5)
async def lookup_hotel(location: str) -> str:
return f"Here are some hotels in {location}: hotel1, hotel2, hotel3."
async def lookup_flight(origin: str, destination: str) -> str:
return f"Here are some flights from {origin} to {destination}: flight1, flight2, flight3."
async def book_trip() -> str:
return "Your trip is booked!"
travel_advisor = AssistantAgent(
"Travel_Advisor",
model_client,
tools=[book_trip],
description="Helps with travel planning.",
)
hotel_agent = AssistantAgent(
"Hotel_Agent",
model_client,
tools=[lookup_hotel],
description="Helps with hotel booking.",
)
flight_agent = AssistantAgent(
"Flight_Agent",
model_client,
tools=[lookup_flight],
description="Helps with flight booking.",
)
termination = TextMentionTermination("TERMINATE")
team = SelectorGroupChat(
[travel_advisor, hotel_agent, flight_agent],
model_client=model_client,
termination_condition=termination,
model_context=model_context,
)
await Console(team.run_stream(task="Book a 3-day trip to new york."))
asyncio.run(main())
"""
component_config_schema = SelectorGroupChatConfig
component_provider_override = "autogen_agentchat.teams.SelectorGroupChat"
def __init__(
self,
participants: List[ChatAgent],
model_client: ChatCompletionClient,
*,
termination_condition: TerminationCondition | None = None,
max_turns: int | None = None,
runtime: AgentRuntime | None = None,
selector_prompt: str = """You are in a role play game. The following roles are available:
{roles}.
Read the following conversation. Then select the next role from {participants} to play. Only return the role.
{history}
Read the above conversation. Then select the next role from {participants} to play. Only return the role.
""",
allow_repeated_speaker: bool = False,
max_selector_attempts: int = 3,
selector_func: Optional[SelectorFuncType] = None,
candidate_func: Optional[CandidateFuncType] = None,
custom_message_types: List[type[BaseAgentEvent | BaseChatMessage]] | None = None,
emit_team_events: bool = False,
model_client_streaming: bool = False,
model_context: ChatCompletionContext | None = None,
):
super().__init__(
participants,
group_chat_manager_name="SelectorGroupChatManager",
group_chat_manager_class=SelectorGroupChatManager,
termination_condition=termination_condition,
max_turns=max_turns,
runtime=runtime,
custom_message_types=custom_message_types,
emit_team_events=emit_team_events,
)
# Validate the participants.
if len(participants) < 2:
raise ValueError("At least two participants are required for SelectorGroupChat.")
self._selector_prompt = selector_prompt
self._model_client = model_client
self._allow_repeated_speaker = allow_repeated_speaker
self._selector_func = selector_func
self._max_selector_attempts = max_selector_attempts
self._candidate_func = candidate_func
self._model_client_streaming = model_client_streaming
self._model_context = model_context
def _create_group_chat_manager_factory(
self,
name: str,
group_topic_type: str,
output_topic_type: str,
participant_topic_types: List[str],
participant_names: List[str],
participant_descriptions: List[str],
output_message_queue: asyncio.Queue[BaseAgentEvent | BaseChatMessage | GroupChatTermination],
termination_condition: TerminationCondition | None,
max_turns: int | None,
message_factory: MessageFactory,
) -> Callable[[], BaseGroupChatManager]:
return lambda: SelectorGroupChatManager(
name,
group_topic_type,
output_topic_type,
participant_topic_types,
participant_names,
participant_descriptions,
output_message_queue,
termination_condition,
max_turns,
message_factory,
self._model_client,
self._selector_prompt,
self._allow_repeated_speaker,
self._selector_func,
self._max_selector_attempts,
self._candidate_func,
self._emit_team_events,
self._model_context,
self._model_client_streaming,
)
[文档]
def _to_config(self) -> SelectorGroupChatConfig:
return SelectorGroupChatConfig(
participants=[participant.dump_component() for participant in self._participants],
model_client=self._model_client.dump_component(),
termination_condition=self._termination_condition.dump_component() if self._termination_condition else None,
max_turns=self._max_turns,
selector_prompt=self._selector_prompt,
allow_repeated_speaker=self._allow_repeated_speaker,
max_selector_attempts=self._max_selector_attempts,
# selector_func=self._selector_func.dump_component() if self._selector_func else None,
emit_team_events=self._emit_team_events,
model_client_streaming=self._model_client_streaming,
model_context=self._model_context.dump_component() if self._model_context else None,
)
[文档]
@classmethod
def _from_config(cls, config: SelectorGroupChatConfig) -> Self:
return cls(
participants=[BaseChatAgent.load_component(participant) for participant in config.participants],
model_client=ChatCompletionClient.load_component(config.model_client),
termination_condition=TerminationCondition.load_component(config.termination_condition)
if config.termination_condition
else None,
max_turns=config.max_turns,
selector_prompt=config.selector_prompt,
allow_repeated_speaker=config.allow_repeated_speaker,
max_selector_attempts=config.max_selector_attempts,
# selector_func=ComponentLoader.load_component(config.selector_func, Callable[[Sequence[BaseAgentEvent | BaseChatMessage]], str | None])
# if config.selector_func
# else None,
emit_team_events=config.emit_team_events,
model_client_streaming=config.model_client_streaming,
model_context=ChatCompletionContext.load_component(config.model_context) if config.model_context else None,
)