When using LangChain with the GPT-4 model for summarization, an error occurs: ValueError: Got unknown type S. This error does not occur when using the GPT-3.5-turbo model instead of GPT-4. The error arises from the _convert_message_to_dict function in the langchain.chat_models.openai module when attempting to convert messages to a dictionary format.
The Solutions:
Solution 1: Replace PromptTemplate with ChatPromptTemplate
As llm uses ChatOpenAI model, it’s necessary to change the prompt template to ChatPromptTemplate instead of PromptTemplate. Additionally, change the human message prompt to a ChatPromptTemplate using from_template function.
Q&A
How to fix ValueError: Got unknown type S when using GPT-4 with LangChain for Summarization?
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Replace your PromptTemplate with a ChatPromptTemplate since it’s a ChatOpenAI model.
Video Explanation:
The following video, titled "How to install Unstructured for Langchain Document loaders ...", provides additional insights and in-depth exploration related to the topics discussed in this post.
I wish I had found this video before wasting 2 hours. New to coding and my one main gripe is how user 'unfriendly' all the set up steps are.
