langchain/memory/chat_message_histories/zep.py/ZepChatMessageHistory/messages
class ZepChatMessageHistory:    def messages(self) -> List[BaseMessage]:  # type: ignore
        """Retrieve messages from Zep memory"""
        zep_memory: Optional[Memory] = self._get_memory()
        if not zep_memory:
            return []

        messages: List[BaseMessage] = []
        # Extract summary, if present, and messages
        if zep_memory.summary:
            if len(zep_memory.summary.content) > 0:
                messages.append(HumanMessage(content=zep_memory.summary.content))
        if zep_memory.messages:
            msg: Message
            for msg in zep_memory.messages:
                if msg.role == "ai":
                    messages.append(AIMessage(content=msg.content))
                else:
                    messages.append(HumanMessage(content=msg.content))

        return messages