response = retrieval_chain.invoke 실행 에러 질문

학Chroma DB를 활용하여 PDF 파일에 대해 RAG 기반 질의응답 구현 (실습)의 29:00 에 있는 코드를 똑같이 실행했는데, 다음과 같은 에러가 발생했습니다.

from langchain_openai import ChatOpenAI
from langchain.chains.combine_documents import create_stuff_documents_chain
from langchain.chains import create_retrieval_chain

model = ChatOpenAI(model ='gpt-3.5-turbo-0125', temperature=0, 
                   api_key=OPENAI_API_KEY)

document_chain = create_retrieval_chain(model, prompt)

retrieval_chain = create_retrieval_chain(retriever, document_chain)

response = retrieval_chain.invoke({"input": "what is the attention mechanism in transformers?"})

에러 메시지

Cell In[163], line 1 ----> 1 response = retrieval_chain.invoke({"input": "what is the attention mechanism in transformers?"}) 2 print(response)

ValueError: Invalid input type <class 'dict'>. Must be a PromptValue, str, or list of BaseMessages.

Output is truncated. View as a scrollable element or open in a text editor. Adjust cell output settings...

document_chain = create_stuff_documents_chain(model, prompt)