I’m trying to follow along to this tutorial https://www.youtube.com/watch?v=E2shqsYwxck (Building Corrective RAG from scratch with open-source, local LLMs) with source code here: https://github.com/langchain-ai/langgraph/blob/main/examples/rag/langgraph_crag_local.ipynb. I am getting the following error at the index section (Code followed by error output in image).