Bird
0
0

Why does this code raise an error?

medium📝 Debug Q7 of 15
LangChain - RAG Chain Construction
Why does this code raise an error? 
retriever = ContextualCompressionRetriever(base_retriever=None)
results = retriever.get_relevant_documents('query')
Abase_retriever cannot be None; it must be a valid retriever
Bget_relevant_documents requires a list query
CContextualCompressionRetriever does not have get_relevant_documents method
DThe query string is too short
Step-by-Step Solution
Solution:

  1. Step 1: Analyze base_retriever argument

    Passing None means no valid retriever is provided, which is invalid.

  2. Step 2: Confirm method and query validity

    Method exists and query type is valid; error is due to None base retriever.

  3. Final Answer:

    base_retriever cannot be None; it must be a valid retriever -> Option A

  4. Quick Check:

    base_retriever must be valid, not None [OK]
Quick Trick: Never pass None as base retriever [OK]
Common Mistakes:
  • Passing None instead of a retriever
  • Misunderstanding method requirements
  • Assuming query length causes error

Want More Practice?

15+ quiz questions · All difficulty levels · Free

Free Signup - Practice All Questions
More LangChain Quizzes
Conversational RAG - Memory-augmented retrieval - Quiz 2easy Conversational RAG - Question reformulation with history - Quiz 12easy Conversational RAG - Handling follow-up questions - Quiz 1easy Document Loading - Directory loader for bulk documents - Quiz 13medium Document Loading - Loading web pages with WebBaseLoader - Quiz 13medium Document Loading - Why document loading is the RAG foundation - Quiz 2easy Embeddings and Vector Stores - FAISS vector store setup - Quiz 13medium RAG Chain Construction - Source citation in RAG responses - Quiz 6medium Text Splitting - Semantic chunking strategies - Quiz 12easy Text Splitting - Overlap and chunk boundaries - Quiz 9hard