RAG Chain fails with TypeError

[murdockcrc]

Hi

I have just copied your code in a notebook and tried to run as-is for a quick test.

However, this line fails to run:

rag_chain = {"sessions": retriever, "question": RunnablePassthrough()} | prompt | llm

with the following error:

TypeError: Expected a Runnable, callable or dict.Instead got an unsupported type: <class 'langchain_core.runnables.base.RunnableBinding'>

As there is no version pinning in the requirements.txt file, I am curious if you can repro this same error with the latest version of langchain, or comment on which version works for you. Thanks.