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# Source code for langchain_community.chat_loaders.utils

    """Utilities for chat loaders."""
    from copy import deepcopy
    from typing import Iterable, Iterator, List

    from langchain_core.chat_sessions import ChatSession
    from langchain_core.messages import AIMessage, BaseMessage

    def merge_chat_runs_in_session(
        chat_session: ChatSession, delimiter: str = "\n\n"
    ) -> ChatSession:
        """Merge chat runs together in a chat session.

        A chat run is a sequence of messages from the same sender.

        Args:
            chat_session: A chat session.

        Returns:
            A chat session with merged chat runs.
        """
        messages: List[BaseMessage] = []
        for message in chat_session["messages"]:
            if not isinstance(message.content, str):
                raise ValueError(
                    "Chat Loaders only support messages with content type string, "
                    f"got {message.content}"
                )
            if not messages:
                messages.append(deepcopy(message))
            elif (
                isinstance(message, type(messages[-1]))
                and messages[-1].additional_kwargs.get("sender") is not None
                and messages[-1].additional_kwargs["sender"]
                == message.additional_kwargs.get("sender")
            ):
                if not isinstance(messages[-1].content, str):
                    raise ValueError(
                        "Chat Loaders only support messages with content type string, "
                        f"got {messages[-1].content}"
                    )
                messages[-1].content = (
                    messages[-1].content + delimiter + message.content
                ).strip()
                messages[-1].additional_kwargs.get("events", []).extend(
                    message.additional_kwargs.get("events") or []
                )
            else:
                messages.append(deepcopy(message))
        return ChatSession(messages=messages)

    def merge_chat_runs(chat_sessions: Iterable[ChatSession]) -> Iterator[ChatSession]:
        """Merge chat runs together.

        A chat run is a sequence of messages from the same sender.

        Args:
            chat_sessions: A list of chat sessions.

        Returns:
            A list of chat sessions with merged chat runs.
        """
        for chat_session in chat_sessions:
            yield merge_chat_runs_in_session(chat_session)

    def map_ai_messages_in_session(chat_sessions: ChatSession, sender: str) -> ChatSession:
        """Convert messages from the specified 'sender' to AI messages.

        This is useful for fine-tuning the AI to adapt to your voice.
        """
        messages = []
        num_converted = 0
        for message in chat_sessions["messages"]:
            if message.additional_kwargs.get("sender") == sender:
                message = AIMessage(
                    content=message.content,
                    additional_kwargs=message.additional_kwargs.copy(),
                    example=getattr(message, "example", None),
                )
                num_converted += 1
            messages.append(message)
        return ChatSession(messages=messages)

    def map_ai_messages(
        chat_sessions: Iterable[ChatSession], sender: str
    ) -> Iterator[ChatSession]:
        """Convert messages from the specified 'sender' to AI messages.

        This is useful for fine-tuning the AI to adapt to your voice.
        """
        for chat_session in chat_sessions:
            yield map_ai_messages_in_session(chat_session, sender)