如何在微软的bot框架中获取bot发送给用户的最后一条消息？或者可以通过连接器api更新用户状态？

from botbuilder.core import ActivityHandler, TurnContext

class MyBot(ActivityHandler):
    async def on_message_activity(self, turn_context: TurnContext):
        # 获取最后一条消息
        last_message = turn_context.activity.text

        # 处理最后一条消息
        # ...

        await turn_context.send_activity("回复用户的消息")

from botbuilder.core import ActivityHandler, TurnContext, ConversationState, UserState

class MyBot(ActivityHandler):
    def __init__(self, conversation_state: ConversationState, user_state: UserState):
        self.conversation_state = conversation_state
        self.user_state = user_state

    async def on_message_activity(self, turn_context: TurnContext):
        # 获取用户状态
        user_state = await self.user_state.get(turn_context, dict)

        # 更新用户状态
        user_state["key"] = "value"

        # 获取对话状态
        conversation_state = await self.conversation_state.get(turn_context, dict)

        # 更新对话状态
        conversation_state["key"] = "value"

        await turn_context.send_activity("回复用户的消息")