langchain/memory/chat_message_histories/zep.py/ZepChatMessageHistory/zep_messages
class ZepChatMessageHistory:    def zep_messages(self) -> List[Message]:
        """Retrieve summary from Zep memory"""
        zep_memory: Optional[Memory] = self._get_memory()
        if not zep_memory:
            return []

        return zep_memory.messages