[Python] How to persist LangChain conversation memory (save and load)?

I'm creating a conversation like so:

llm = ChatOpenAI(temperature=0, openai_api_key=OPENAI_API_KEY, model_name=OPENAI_DEFAULT_MODEL)
conversation = ConversationChain(llm=llm, memory=ConversationBufferMemory())


But what I really want is to be able to save and load that ConversationBufferMemory() so that it's persistent between sessions. There doesn't seem to be any obvious tutorials for this but I noticed "Pydantic" so I tried to do this:

saved_dict = conversation.memory.chat_memory.dict()
cm = ChatMessageHistory(**saved_dict) # or cm = ChatMessageHistory.parse_obj(saved_dict)


But this fails:

ValidationError: 6 validation errors for ChatMessageHistory
messages -> 0
Can't instantiate abstract class BaseMessage with abstract method type (type=type_error)


Thoughts? I'd love links to any sort of guide, repo, reference, etc.

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